New basal bird from China reveals the morphological diversity in early birds

Over the past three decades, representatives of all major Mesozoic bird groups have been reported from the Early Cretaceous Jehol Biota of northeastern China. A new species, Chongmingia zhengi, reported in the journal of Scientific Reports on 25 January 2016, sheds light on the early evolution of birds. Phylogenetic analyses indicate that it is basal to the dominant Mesozoic avian clades Enantiornithes and Ornithuromorpha, and represents a new basal avialan lineage. This new discovery adds to our knowledge regarding the phylogenetic differentiation and morphological diversity in early avian evolution.

This new species, represented by a single new skeleton from the Early Cretaceous Jiufotang Formation of the Jehol Group in Dapingfang, Liaoning Province, China. The generic name is from the Mandarin word Chongming, referring to a Chinese mythological bird. The specific epithet is in honour of Mr. ZHENG Xiaoting for his generous contribution in the establishment of the Shandong Tianyu Museum of Nature.

The new specimen is a partial skeleton with associated soft tissues and gastroliths, missing the skull and most of the caudal vertebrae. Comparative studies indicate that it is a large non-ornithothoracine bird distinguishable from the known basal avialans by a combination of features.

The furcula of Chongmingia is rigid (reducing its efficiency), consequently requiring more power for flight. However, the elongated forelimb and the large deltopectoral crest on the humerus might indicate that the power was available. The unique combination of features present in this species demonstrates that numerous evolutionary experimentations took place in the early evolution of powered flight.

Histological studies indicate Chongmingia had a moderately elevated growth rate relative to the long-tailed Archaeopteryx and Jeholornis. Furthermore, other morphological features, along with the evolutionary pattern drawn from other basal birds, reveal mosaic evolution and numerous evolutionary experiments relating to powered flight early in the evolution of birds.

The occurrence of gastroliths further confirms that herbivory was common among basal birds. The Jehol birds faced competition with pterosaurs, and occupied sympatric habitats with nonavian theropods, some of which consumed birds. Thus, avialan herbivory may have reduced ecological competition from carnivorous close relatives and other volant vertebrates early in their evolutionary history.

“Although our analysis suggests that the new specimen may represent the most phylogenetically basal Cretaceous bird known to date, this phylogenetic hypothesis should be treated with caution given the incomplete preservation of the skeleton and low phylogenetic support values,” said lead author Dr. WANG Min, Institute of Vertebrate Paleontology and Paleoanthropology (IVPP) of the Chinese Academy of Sciences.  Science Daily  Original web page at Science Daily


Woodpecker drumming signals wimp or warrior

Animal behavior researchers at Wake Forest University have found that the highly territorial downy woodpecker interprets drumming intensity from adversaries to figure out who is or isn’t a threat.

Instead of a distinctive song, woodpeckers bang on trees with their bills to create a sound called drumming. The birds use it to communicate when they want to attract a mate or defend a territory. Wake Forest assistant professor of biology Matthew Fuxjager and his research team, which consists of graduate student Eric Schupee and several undergraduates, tested how woodpecker pairs perceived the drumming to see how it influenced territorial interaction and coordination of defensive behavior.

“Partners will actually coordinate or cooperate with how they fight depending on who they are fighting. They size up their opponent and decide whether they need to work together,” Fuxjager said. “In short, it means an intruder woodpecker with a short drum is perceived as wimpier, while a long drum signifies a tough guy intruder.”

The team conducted behavioral experiments by recording drumming sounds from males and then playing them back, manipulating them to territory holders, to see what kind of behavioral response that would elicit, said Fuxjager, who studies physiological and behavioral mechanisms of social biology, particularly in bird species. The research was conducted in the woods on the Wake Forest campus and in the surrounding Winston-Salem community

What they found is that if you present a breeding pair of woodpeckers with a longer drum from a more aggressive intruder, the pair begins to coordinate their territorial defense behavior and coordinate how they attack the intruder; whereas, a shorter drum from a weaker intruder meant that the resident pair didn’t bother to coordinate a response.

Overall, Fuxjager said these findings, recently published in the journal Behavioral Ecology and Sociobiology, provide insight into aggressive behavior in birds in general and how individuals coordinate behavior to accomplish shared goals or tasks.

“When you walk through the woods and you hear a woodpecker, most people think they are looking for food, but that’s actually a social signal they use.”  Science Daily  Original web page at Science Daily


Bird communication: Chirping with syntax

Language is one of the defining characteristics of human beings: It enables us to generate unlimited meanings from a finite number of phonetic elements. Using syntactic rules, humans are able to combine words to form phrases and sentences, and thus ascribe meaning to various things and activities. Research on communication systems suggests that non-human primates and birds, too, have evolved the ability to assign meaning to arbitrary vocal elements. But until now, the evolution of syntax has been considered unique to human language. Warning signal plus mating call means “flock together”

Evolutionary biologists at The Graduate University for Advanced Studies in Japan, the Uppsala University in Sweden and the University of Zurich are now challenging this view. For the first time, these researchers have demonstrated that Japanese great tits (Parus minor) have developed syntactic rules. These small birds are known for their large vocal repertoire, and the team discovered that they use a variety of calls and combinations of calls to interact with one another in specific situations. The combination of sounds such as the “ABC calls,” for instance, means “watch out!.” The great tits use them when a sparrowhawk or another predator is nearby — a potentially dangerous situation. By contrast, “D calls” mean “come over here,” a call the birds use after discovering a new source of food or when wanting their partner to come to the nest.

Tits frequently combine these two calls into ABC-D calls when, for instance, the birds encounter predators and join forces to deter them. When hearing a recording of these calls played in the natural order of ABC-D, the birds are alarmed and flock together. When, however, the call ordering is artificially reversed to D-ABC, the birds do not respond.

The researchers have therefore drawn the conclusion that syntax is not unique to human language: It has also evolved independently in birds. “The results lead to a better understanding of the underlying factors in the evolution of syntax. Because the tits combine different calls, they are able to create new meaning with their limited vocabulary. That allows them to trigger different behavioral reactions and coordinate complex social interactions,” says Dr. Michael Griesser, at the Institute of Anthropology at the University of Zurich. He believes these factors may well have contributed to the development of language in humans.   Science Daily  Original web page at  Science Daily


Tunnel through the head: Internally coupled ears enable directional hearing in animals

Humans use the time delay between the arrival of a sound wave at each ear to discern the direction of the source. In frogs, lizards and birds the distance between the ears is too small. However, they have a cavity connecting the eardrums, in which internal and external sound waves are superimposed. Using a universal mathematical model, researchers at the Technical University of Munich (TUM) have now for the first time shown how new signals are created in this “inner ear” used by animals for localizing sounds.

Whether perceiving an encroaching predator or finding prey in the dark, precisely localizing the source of a sound is indispensable in the animal kingdom. Almost all mammals, including humans, localize sound sources horizontally via the the delay in time in which sound signals arrive at each ear. Using this time difference the brain can calculate the direction from which the sound emanated.

Frogs, many reptiles and birds do not have this option since the distance between their ears often measures merely a few centimeters. The time difference is thus so small that it cannot be processed by the brain. To make up for this disadvantage theses animals have developed a simple albeit very effective system: An air-filled cavity connects the eardrums of the two ears.

This cavity, which runs right through the head, couples the eardrums. The scientists refer to this as “internally coupled ears” or ICE. This “tunnel in the head” is clearly visible when light falls into one ear of a gecko: The light then shines out of the other ear.

Unlike humans, the animals perceive not only external signals, but also a superposition of external sound waves with those that are created internally through the coupling of the two sides. Scientists have determined in experiments that animals use the resulting signals for pinpointing sound sources. But what exactly happens in the coupled ears remained a mystery.

Now, scientists working led by Leo van Hemmen, Professor of Theoretical Biophysics at the Technical University of Munich (TUM) have for the first time developed an universal mathematical model that describes how sound waves propagate through the internally coupled ears and which clues for localizing sound sources are created in the process.

“Our model is applicable to all animals with this kind of hearing system, regardless that the cavities between the eardrums of the various species look very different,” explains van Hemmen. “We now understand what exactly happens inside the ears of these animals and can both explain and predict the results of experiments in all sorts of animals.” Over 15,000 species have internally coupled ears — that is more than half of all land-dwelling vertebrate animals.

Using their model, van Hemmen and his team discovered that the animals have even developed two different methods of hearing with internally coupled ears. They occur in different frequency domains and augment each other.

In sounds below the fundamental frequency of the eardrum the time difference in the superposition of the internal and external signals is amplified up to five-fold. That is sufficient to facilitate sound localization.

In higher frequencies the time difference can no longer be evaluated. Here, another property of the signal becomes relevant: The difference in the amplitude, i.e. the loudness, of the sound perceived by the ears. “The amplitude difference occurs solely through the coupling of the two ears,” explains van Hemmen. “That was a surprising result.”

This new insight on the mechanisms and especially the advantages of hearing with internally coupled ears is also relevant for industrial applications. It is conceivable that robots will be equipped with this kind of hearing system. “I can very well imagine applications in robotics, because this kind of amplification doesn’t need energy” expresses van Hemmen. In the future van Hemmen and his team of scientists hope to refine their model in collaboration with the experimental work of colleagues. Science Daily  Original web page at Science Daily


* Songbird’s reference genome illuminate key role of epigenetics in evolution of memory and learning

A well-known songbird, the great tit, has revealed its genetic code, offering researchers new insight into how species adapt to a changing planet. Their initial findings suggest that epigenetics — what’s on rather than what’s in the gene — may play a key role in the evolution of memory and learning. And that’s not just true for birds. An international research team led by the Netherlands Institute of Ecology (NIOO-KNAW) and Wageningen University will publish these findings in Nature Communications on Monday.

“People in our field have been waiting for this for decades,” explain researchers Kees van Oers and Veronika Laine from the Netherlands Institute of Ecology. The reference genome of their favourite model species, the great tit, is “a powerful toolbox that all ecologists and evolutionary biologists should know about.”

Coming from a single Dutch bird, the genetic code of the assembled reference genome will help to reveal the genetic basis of phenotypic evolution. This is essential for understanding how wild species adapt to our changing planet.

In addition to looking at the genome, the research team have also determined the so-called transcriptome and methylome. The latter belongs to the field of epigenetics: the study of what you can inherit not in but ‘on’ your genes. Specific DNA sequences in the genome can be ‘methylated’: methyl groups are added to them, modifying how the genes function.

The research team sequenced the complete genomes of a further 29 great tit individuals from different parts of Europe. This enabled them to identify regions in the great tit’s genome that have been under selection during recent evolution of the bird. These regions appeared to be overrepresented for genes related to learning and cognition.

“The great tit has evolved to be smart,” says Van Oers. “Very smart.” It’s not your average bird, as it belongs to the top 3% smartest birds when it comes to learning new behaviour. That makes it a perfect candidate for research into the evolution of learning, memory and cognitive processes.

What that research has revealed are so-called conserved patterns of methylation in those same regions, present not only in birds but also in humans and other mammals. It’s evidence of a correlation between epigenetic processes such as methylation and the rate of molecular evolution: “the more methylation, the more evolution.”

And so the great tit has once more proved that its role as a model species in a variety of biological research fields for over 60 years is by no means coincidental. Science Daily  Original web page at Science Daily


The magnetic compass of birds is affected by polarized light

The magnetic compass that birds use for orientation is affected by polarised light. This previously unknown phenomenon was discovered by researchers at Lund University in Sweden.

The discovery that the magnetic compass is affected by the polarisation direction of light was made when trained zebra finches were trying to find food inside a maze. The birds were only able to use their magnetic compass when the direction of the polarised light was parallel to the magnetic field, not when perpendicular to the magnetic field.

“We were expecting an effect, but not one so major that it would lead to complete disorientation when the direction of the polarisation of light was perpendicular to the direction of the magnetic field,” says Rachel Muheim, who was in charge of the study.

It is still unclear how the different directions of polarised light in relation to the Earth’s magnetic field affect birds in the wild. The researchers have put forward a thesis that the birds use it to accentuate the magnetic field during sunrise and sunset — times of day when migratory birds are believed to determine their direction and calibrate their compasses before migrating.

“In the middle of the day, when the polarised light is approximately perpendicular to the magnetic field, it can be an advantage that the magnetic field is less visible, so that it does not interfere at a time when visibility is important to locate food and to detect predators,” says Rachel Muheim.  Science Daily  Original web page at Science Daily


Small birds prefer flying in company

Until now, scientists had observed that some large birds are sociable amongst each other. However, a new study has confirmed that this unique characteristic can also be seen among smaller birds such as the Eurasian siskin, a bird which is able to form bonds that last for a number of years as well as travel long distances in the company of these birds. This intimacy may favour reproduction in addition to facilitating the process of adjusting to a new place.

The sociability of swans, geese and birds of the crow family has been studied and is well understood by scientists. These are large birds that tend to form stable, long-lasting bonds. This peculiarity, however, had not been observed in smaller birds, such is the case with the Eurasian siskin (Carduelis spinus). A study published in ‘Bird Study’ reveals that this species has a tendency to travel long distances in groups over the course of several years. Up to this time, researchers from the Natural Sciences Museum of Barcelona -the leaders of this study- had discovered that female Eurasian siskins in captivity prefer to mate with males that they know. Nevertheless, the investigators still needed to prove that these birds, when out in nature, do indeed live together for periods of time that are long enough for these specimens to interact and to get to know each other.

“In this study we show how the Eurasian siskin is able to form stable group relationships lasting for periods of several years in addition to travelling in each other’ company over distances spanning more than 1,000 km,” points out Juan Carlos Senar, lead author of this study and a scientist at the museum.

The research team used data from the ‘European Union for Bird Ringing’ (EURING) -the European institution in charge of banding and tracking birds- in order to examine the data recorded on 42,707 Eurasian siskins between 1907 and 2011. For greater accuracy, the experts limited their study to those birds that had travelled distances greater than 50 km from the place where they had been banded — a distance that exceeds the maximum number of kilometres that these birds tend to travel in a single day (10-40 km).

The findings demonstrated that Eurasian siskins can remain together in the same group for up to four years. The results also showed that they can travel with other individuals for distances up to 1,300 km. With regard to the types of groups the birds travelled in, the records confirm that they could be either single-sex or mixed-sex groups.

Senar also draws attention to the fact that “what is important is that several groups of individuals were detected travelling together for hundreds of kilometres, and that these groups included both males with females (possible partners), as well as single-sex groups, thus implying that these bonds are not only formed between mating partners, but that they can also form between groups of friends with social ties.”

Until now, some studies had confirmed a marked sociability in small birds such as the pine siskin (Carduelis pinus) and the common redpoll (Acanthis flammea). These studies, however, were conducted over the course of one winter, thus resulting in data corresponding to relatively short travel distances and a period of time of only a few months.

Senar and his team wanted to replicate these results in the Eurasian siskin by studying the journeys made during the entire biological period and throughout the lifetime of an individual. “This study conducted on the Eurasian siskin also carries the added importance of the fact that this species, unlike the European goldfinch (Carduelis carduelis) or the European greenfinch (Carduelis chloris), is nomadic, meaning that these specimens fly to a different destination each year,” indicates the scientist.

Thus, “if two individuals are recaptured together hundreds of kilometres from where they were originally captured, this is not because both were going to independently spend the winter in the same place and just happened to both be there. Rather, these two individuals would have had to purposefully travel together,” explains the researcher.

The study has also revealed that these individuals prefers to mate with others that they are familiar with — something which may be an important mechanism to aid in adjusting to new places. For this to be possible, individuals must interact with each other over long periods of time, something that, as demonstrated in this study, is also characteristic of these little birds.  Science Daily  Original web page at Science Daily


Orangutans: Lethal aggression between females

Researchers have for the first time witnessed the death of a female orangutan at the hands of another female. Even more extraordinary is that the perpetrator recruited a male orangutan as a hired gun to help her corner and attack the victim. Before this observation, lethal fights between females had never been observed in orangutans; in other primates such fights occur mainly between males, according to Anna Marzec of the University of Zurich in Switzerland. She is the lead author of a report on the fatal incident, which appears in Springer’s journal Behavioral Ecology and Sociobiology.

Aggression serves ultimately to gain access to limited resources. Although aggression among primates is frequent, lethal attacks are very rare, especially among female individuals. Female Bornean orangutans live alone and typically settle in or near the area where they were born, whereas males generally disperse. The two sexes regularly associate only during the few months before a female orangutan is ready to conceive, which happens approximately every seven years.

The research team around Marzec had been following a population of Bornean orangutans (Pongo pygmaeus wurmbill) in the swamp forests of Indonesia’s Mawas Reserve since 2003 and already collected over 26,000 hours of information on the adult females alone when they observed the fatal attack in July 2014. During this period, only six female-female attacks had been observed, none of which had caused visible injuries. Other long-term studies of orangutans similarly have never reported such violent female attacks.

The case involved Kondor, a young female who had lost her infant just weeks before, and Sidony, a much older resident female who did not interact much with neighbouring apes. The two females had a history of aggressive interaction: a few years earlier the researchers had witnessed an encounter between them during which Sidony hit and bit Kondor, who had apparently approached Sidony’s seven-year-old daughter.

In the week before the lethal attack, Kondor was seen with a male called Ekko. The two of them encountered Sidony and her dependent son. After Ekko sexually inspected Sidony, he returned to Kondor to mate with her. Kondor interrupted these sexual activities when Sidony started to move away, and attacked her.

Ekko joined the fight, which lasted 33 minutes. They continuously attacked as a coordinated team. While one attacked, the other blocked the victim’s escape route. Kondor instigated two further shorter attacks. Ekko, who had long canines typical of a male, inflicted the most serious injuries and effectively prevented Sidony’s escape.

The dynamics changed when another male, Guapo, arrived and chased Ekko away. Guapo then mated with Sidony. Kondor continued to harass and bite her. Whenever Sidony screamed, Guapo positioned himself between the females or escorted the older ape away. Sidony sustained major injuries in the first part of the attack. Although Guapo successfully protected her from further damaging attacks, Sidony died two weeks later.

The case does not comfortably fit into the pattern of joint coalitional killings normally seen in primates. The attack involved between-sex coalitions, with the males being either the back-up or bodyguard of a female.

“This is quite unexpected, as in wild orangutans males and females have never been reported to form coalitions before,” says Marzec. “It is also the first report of males supporting females in their conflicts, with lethal outcome.”  Science Daily  Original web page at Science Daily


Singing in the brain: Songbirds sing like humans

A songbirds’ vocal muscles work like those of human speakers and singers, finds a study recently published in the Journal of Neuroscience. The research on Bengalese finches showed that each of their vocal muscles can change its function to help produce different parameters of sounds, in a manner similar to that of a trained opera singer.

“Our research suggests that producing really complex song relies on the ability of the songbirds’ brains to direct complicated changes in combinations of muscles,” says Samuel Sober, a biologist at Emory University and lead author of the study. “In terms of vocal control, the bird brain appears as complicated and wonderful as the human brain.”

Pitch, for example, is important to songbird vocalization, but there is no single muscle devoted to controlling it. “They don’t just contract one muscle to change pitch,” Sober says. “They have to activate a lot of different muscles in concert, and these changes are different for different vocalizations. Depending on what syllable the bird is singing, a particular muscle might increase pitch or decrease pitch.”

Previous research has revealed some of the vocal mechanisms within the human “voice box,” or larynx. The larynx houses the vocal cords and an array of muscles that help control pitch, amplitude and timbre.

Instead of a larynx, birds have a vocal organ called the syrinx, which holds their vocal cords deeper in their bodies. While humans have one set of vocal cords, a songbird has two sets, enabling it to produce two different sounds simultaneously, in harmony with itself.

“Lots of studies look at brain activity and how it relates to behaviors, but muscles are what translates the brain’s output into behavior,” Sober says. “We wanted to understand the physics and biomechanics of what a songbird’s muscles are doing while singing.”

The researchers devised a method involving electromyography (EMG) to measure how the neural activity of the birds activates the production of a particular sound through the flexing of a particular vocal muscle.

The results showed the complex redundancy of the songbird’s vocal muscles. “It tells us how complicated the neural computations are to control this really beautiful behavior,” Sober says, adding that songbirds have a network of brain regions that non-songbirds do not.  Science Daily  Original web page at Science Daily


How birds learn through imitation

Precise changes in brain circuitry occur as young zebra finches go from listening to their fathers’ courtship songs to knowing the songs themselves, according to a study led by neuroscientists at NYU Langone Medical Center and published online in a Science cover report on January 14.

The study reveals how birds learn songs through observation and practice, and the authors hope the work will guide future research into how patients with brain injuries might reacquire the ability to learn skilled behaviors like speech.

“While we have known for decades that adolescent songbirds only learn their songs if exposed to a tutor, we believe our study is the first to detail changes in nerve networks that make this mastery possible in maturing brains,” says senior study investigator Michael Long, PhD.

“Our results show that finch song learning reflects a ‘dance’ inside the brain’s vocal control center between nerve cells that capture information as the bird listens and those that direct muscle movement as it sings,” says Long, an assistant professor of neuroscience at NYU Langone.

In the current study, led by Daniela Vallentin, PhD, and Georg Kosche in the NYU Neuroscience Institute, the research team found that early in adolescence, just listening to a father’s song turns on the same brain cell networks that the young bird will use later to sing the song once learned.

A second result revolves around a set of nerve cells in the brain — inhibitory interneurons — which dampen the activity of surrounding nerves to sculpt sensory input into function. Researchers found that interneurons suppress the impact of each note in a father’s song as soon as it is learned, “locking” it into the younger bird’s memory piece by piece.

“Our research advances the understanding of how skilled behaviors are learned, and the role played by sensory inhibition in making memorized patterns permanent,” says Long. Such a framework, he says, could apply to complex behaviors in people, such as dancing or hitting a baseball.

For the study, researchers used electrodes to track brain cell activity in young zebra finches as they learned songs from a mentoring parent over several weeks. Typically zebra finches learn songs during their adolescence, which begins roughly a month after birth and lasts 100 days, during which they practice each song hundreds of thousands of times.

Specifically, researchers found that the influence of the parent on the adolescent’s nerve circuits gradually decreased as songs were learned, and that fast learners had faster brain changes.

The electrode experiments examined the cooperation between premotor neurons that control singing and inhibitory interneurons that together enabled song learning. After the courtship songs were learned, none of the premotor neurons turned on in response to a tutor’s song. Inhibitory signals from interneurons had formed “a barrier” over the learned notes, rendering them impervious to parental influence.

Long says the team will next conduct experiments that seek to clarify how networks of inhibitory interneurons “tell the difference” between songbird notes that have been mastered and those still being learned. Knowing that may guide future attempts to roll back inhibitory barriers established as behaviors are learned, making brain circuits available once again for the learning of skilled behaviors lost to injury or stroke.  Science Daily  Original web page at Science Daily


How variation in body size correlates with en-route migration performance in a long-distance migratory songbird?

Researchers relate migration performance to body and wing size in migratory songbirds. The original article “The influence of morphological variation on migration performance in a trans-hemispheric migratory songbird” is available to read and download fully in open access on De Gruyter Online.

Every spring and fall, migratory songbirds around the world make epic journeys from their breeding to their wintering grounds. Ornithologists have long known that not all birds travel at the same speed during the treks, as some individuals tend to stay longer at stopover sites than others. The reason for the varying stopover lengths has usually been attributed to differences in feeding rates. Now, a team of Canadian researchers from the University of Manitoba has determined there is another, very surprising, reason why some birds stay longer at stopover sites than others. In an article, just published in Animal Migration, they conclude that, apparently, it is the physical structure of the birds that determines their performance.

The researchers, led by Lawrence Lam from the University of Manitoba, studied the migrations of individual Purple Martins — small songbirds related to swallows, known for colonial-nesting in Martin houses and hollowed-out gourds. They placed tiny tracking devices (light-level geolocators) on 120 martins from 10 different breeding sites across North America and then recaptured them after the birds had completed their migration. The devices not only provide information on where the birds go during their northward and southward journeys, but they also tell, how long they stay at stopover sites on route.

Eager to determine if body or wing size played role in the migratory rates of the martins, the scientists collected detailed measurements of each bird before they released it. They then compared the birds’ individual body measurements against the number and duration of their stopover periods during the fall and spring migrations. Their analyses demonstrated that larger-bodied birds tend to stay longer at stopover sites during fall migration, but during spring the larger birds actually have shorter and fewer stopovers. In other words, the individual variation in stopover length is influenced by the size of the bird, and by the size of its wings.

“As far back as the late 1800’s, researchers noticed that migratory birds differed in size and shape than non-migratory birds, and they suggested that these features may be beneficial to migrants” comments Dr. Melissa Bowlin of the University of Michigan-Dearborn, who also utilizes tracking technologies in her research of migratory flight performance. Now we know “that smaller-bodied birds were able to migrate faster in autumn,” she adds. “While this is just a first step, analyses such as these should allow us to tease apart the effects (if any) of some of the morphological variables that have been associated with migration for so many years.”

It is yet unclear, if these findings apply to other long-distance migrants, but the current results already pave the way for future investigations on the linkages between physical characteristics and migration performance. The authors recommend that, when studying the migration ecology of long-distance migratory birds, researchers should include information regarding how foraging ability and other factors may impact migratory performance.

“A lot of researchers are now using geolocators to track bird migrants,” says Andy Davis, Editor-in-Chief of Animal Migration, “but this study is the first to combine migration tracking information with individual flight characteristics, and it shows these things are related.”  Science Daily  Original web page at Science Daily


Crows caught on camera fashioning special hook tools

Scientists have been given an extraordinary glimpse into how wild New Caledonian crows make and use ‘hooked stick tools’ to hunt for insect prey. Scientists have been given an extraordinary glimpse into how wild New Caledonian crows make and use ‘hooked stick tools’ to hunt for insect prey.

Dr Jolyon Troscianko, from the University of Exeter, and Dr Christian Rutz, from the University of St Andrews, have captured first video recordings documenting how these tropical corvids fashion these particularly complex tools in the wild.

The pair developed tiny video ‘spy-cameras’ which were attached to the crows, to observe their natural foraging behaviour.

They discovered two instances of hooked stick tool making on the footage they recorded, with one crow spending a minute making the tool, before using it to probe for food in tree crevices and even in leaf litter on the ground. The findings are reported in the Royal Society’s journal Biology Letters on Wednesday, December 23.

Dr Troscianko is a Postdoctoral Research Fellow in Exeter’s Biosciences Department based at the Penryn Campus in Cornwall, who worked on the project while at the University of Birmingham.

He said: “While fieldworkers had previously obtained brief glimpses of hooked stick tool manufacture, the only video footage to date came from baited feeding sites, where tool raw materials and probing tasks had been provided to crows by scientists. We were keen to get close-up video of birds making these tools under completely natural conditions.”

“New Caledonian crows are notoriously difficult to observe, not just because of the challenging terrain of their tropical habitats, but also because they can be quite sensitive to disturbance. By documenting their fascinating behaviour with this new camera technology, we obtained valuable insights into the importance of tools in their daily search for food.”

To obtain a ‘crow’s-eye view’ of this elusive behaviour, the two researchers developed video cameras that are attached to the crows’ tail feathers. The cameras are about the weight of a British 2-pound coin, and a tiny integrated radio beacon let the scientists recover the devices once they had safely detached after a few days. Dr Christian Rutz, Reader in the School of Biology in St Andrews, explains: “These cameras store video footage on a micro-SD card, using technology similar to that found in people’s smart phones. This produced video recordings of stunning quality.”

The team deployed 19 cameras on crows at their chosen dry forest study site, where in hundreds of hours of fieldwork, despite two brief glimpses with binoculars, they had never managed to film crows manufacturing hooked stick tools.

The team were excited to record two instances of this behaviour on footage recovered from ten birds in their latest study.

Troscianko noted: “The behaviour is easy to miss — the first time I watched the footage, I didn’t see anything particularly interesting. Only when I went through it again frame-by-frame, I discovered this fascinating behaviour. Not once, but twice!”

“In one scene, a crow drops its tool, and then recovers it from the ground shortly afterwards, suggesting they value their tools and don’t simply discard them after a single use.” According to Rutz, this observation agrees with recent aviary experiments conducted by his group: “Crows really hate losing their tools, and will use all sorts of tricks to keep them safe. We even observed them storing tools temporarily in tree holes, the same way a human would put a treasured pen into a pen holder.”

New Caledonian crows (Corvus moneduloides) are found on the South Pacific island of New Caledonia. They can use their bills to whittle twigs and leaves into bug-grabbing implements; some believe their tool-use is so advanced that it rivals that of some primates.  Science Daily  Original web page at Science Daily


Few migratory birds adequately protected across migration cycle

Scientists have called for a greater international collaborative effort to save the world’s migratory birds, many of which are at risk of extinction due to loss of habitat along their flight paths.

More than 90 per cent of the world’s migratory birds are inadequately protected due to poorly coordinated conservation around the world, a new study published in the journal Science today reveals.

Led by the ARC Centre of Excellence for Environmental Decisions (CEED), the research found huge gaps in the conservation of migratory birds, particularly across China, India, and parts of Africa and South America. This results in the majority of migratory birds having ranges that are well covered by protected areas in one country, but poorly protected in another.

“More than half of migratory bird species travelling the world’s main flyways have suffered serious population declines in the past 30 years. This is due mainly to unequal and ineffective protection across their migratory range and the places they stop to refuel along their routes,” says lead author Dr Claire Runge of CEED and the University of Queensland.

“A typical migratory bird relies on many different geographic locations throughout its annual cycle for food, rest and breeding. “So even if we protect most of their breeding grounds, it’s still not enough — threats somewhere else can affect the entire population,” she says. “The chain can be broken at any link.

Dr Runge explains that these birds undertake remarkable journeys navigating across land and sea to find refuge as the seasons change, from endurance flights exceeding 10,000 kilometres by bar-tailed godwits to the annual relay of Arctic terns, which fly the equivalent of the distance to the moon and back three times during their lives.

Other examples include the sooty shearwater which flies 64,000 kilometres from the Falkland Islands to the Arctic, and the tiny blackpoll warbler, which flies for three days non-stop across open ocean from eastern Canada to South America.

The CEED study found that of 1,451 migratory bird species, 1,324 had inadequate protection for at least one part of their migration pathway. Eighteen species had no protection in their breeding areas and two species had no protection at all along their whole route.

For migratory bird species listed as threatened on the International Union for Conservation of Nature Red List by BirdLife International, less than three per cent have sufficient protected areas. “For example, the red-spectacled amazon — a migratory parrot of Brazil — is threatened by habitat loss,” says Dr Stuart Butchart, Head of Science at BirdLife International and a co-author of the study. “And yet less than four per cent of its range is protected, and almost none of its seasonal breeding areas in southern Brazil are covered.” The team also examined over 8,200 areas that have been identified as internationally important locations for migratory bird populations. They found that just 22 per cent are completely protected, and 41 per cent only partially overlap with protected areas.

“Establishing new reserves to protect the unprotected sites — and more effectively managing all protected areas for migratory species — is critical to ensure the survival of these iconic species,” Dr Butchart said.

Co-author Associate Professor Richard Fuller of CEED says the results highlight an urgent need to coordinate protected area designation along the birds’ full migration route. “For instance, Germany has protected areas for over 98 per cent of the migratory species that pass its borders, but fewer than 13 per cent of its species are adequately protected across their global range.

“It isn’t just a case of wealthy nations losing their migratory birds to a lack of protection in poorer nations. Many Central American countries, for example, meet the targets for more than 75 per cent of their migratory species, but these same species have less protected area coverage in Canada and USA.”

While protected areas are usually designated by each country, collaborative international partnerships and inter-governmental coordination as well as action are crucial to safeguard the world’s migratory birds. “It won’t matter what we do in Australia or in Europe if these birds are losing their habitat somewhere else — they will still perish. We need to work together far more effectively round the world if we want our migratory birds to survive into the future,” Dr Fuller says.  Science Daily  Original web page at Science Daily


Urban swans’ genes make them plucky

Researchers have discovered that swans’ wariness is partly determined by their genes. The research, which is published in the open access journal BMC Evolutionary Biology, suggests that swans which are genetically predisposed to be timid are more likely to live in non-urban areas, and the findings could have important implications for releasing animals bred in captivity into the wild

It is often assumed that animals that live in urban areas become less wary of humans through habituation, but until now, no research has been conducted which tests whether animals’ preference for an urban or non-urban environment might be genetically determined.

A team of researchers from Victoria University, Deakin University and The University of Melbourne, Australia, conducted a series of tests to establish the wariness of two separate populations of black swans (Cygnus atratus). One population of 80 swans were living in an urban parkland setting, where they frequently encountered humans, while a second population of 20 swans were living around 30km away in a non-urban area, much less frequented by people.

The researchers quantified the birds’ wariness by walking slowly towards them, and then measuring the distance at which the bird flew away, called the Flight Initiation Distance (FID). Separately, they also took blood samples from the two populations of birds so that they could look for variations in two sets of genes — DRD4 and SERT — typically associated with behaviours related to anxiety and harm avoidance in animals.

As expected, the swans living in an urban setting were much bolder than their rural counterparts, with an average FID of 13 meters, compared to 96 meters for the non-urban swans. The genetic tests revealed no significant differences between the two populations in SERT genotypes, but they found five different variants of DRD4 which were associated with different levels of wariness.

The vast majority (88.8%) of the urban swans shared the most common genotype for DRD4, whereas only 60% of the rural swans exhibited this genotype. Of all the swans, 83% with the most common DRD4 genotype had a shorter average FID, suggesting that the birds’ wariness is at least partly determined by their genes.

As swans are typically highly mobile, and have the ability to migrate between different habitats, the researchers conclude that wary swans may be more likely to choose to inhabit a non-urban site, with bolder swans colonising urban areas.

Lead researcher, Wouter van Dongen, says: “Growing global urbanisation means that wild animals are increasingly settling near to humans. Although we often assume that animals become less wary of humans by simply getting used to them, our results suggest that at least part of this response might be genetically determined. This has important implications for conservation, particularly for the introduction of animals bred in captivity, which could in future be screened for genotypes that are associated with wariness, allowing them to be released to a location commensurate with their expected wariness.”  Science Daily  Original  web page at Science Daily


Cuckoo sheds new light on the scientific mystery of bird migration

The cuckoo is not only capable of finding its way from unknown locations; it does this through a highly complex individual decision making process. Such skills have never before been documented in migratory birds. A new study shows that navigation in migratory birds is even more complex than previously assumed. The Center for Macroecology, Evolution and Climate at the University of Copenhagen led the study with the use of miniature satellite tracking technology.

In an experiment, 11 adult cuckoos were relocated from Denmark to Spain just before their winter migration to Africa was about to begin. When the birds were released more than 1,000 km away from their well-known migration route, they navigated towards the different stopover areas used along their normal route.

“The release site was completely unknown to the cuckoos, yet they had no trouble finding their way back to their normal migratory route. Interestingly though, they aimed for different targets on the route, which we do not consider random. This individual and flexible choice in navigation indicates an ability to assess advantages and disadvantages of different routes, probably based on their health, age, experience or even personality traits. They evaluate their own condition and adjust their reaction to it, displaying a complicated behavior which we were able to document for the first time in migratory birds,” says postdoc Mikkel Willemoes from the Center for Macroecology, Evolution and Climate at the University of Copenhagen.

Previously, in 2014, the Center also led a study mapping the complete cuckoo migration route from Denmark to Africa. Here they discovered that during autumn the birds make stopovers in different areas across Europe and Africa. It was these areas the displaced cuckoos aimed for: Of the 11 birds, one flew to Poland, one to the Balkans, one to Chad and three of them flew to the Democratic Republic of Congo. From there, they followed their familiar migration route. The last five birds lost their transmitting signal.

“In order to select an individual strategy, the birds should be capable of balancing perceived gains and risks of several different scenarios. Such a task would require knowledge of the current location in relation to all of the possible goals as well as distances to each of the goals. This tells us that bird migration in general is far more complex than previously assumed,” says Mikkel Willemoes. The study was carried out in collaboration with Doñana Biological Station in Spain and the Max Planck Institute for Ornithology in Germany.

Bird relocation studies have been carried out in the past, but recent satellite technology has made it possible for the first time to track the complete migration of a relocated species and reveal individual responses.

“We have received remarkable details on the movement of adult birds. The next step is to develop smaller transmitters that will enable us to follow young cuckoos on a relocation flight. Without prior migration experience, their choices will reveal new insight on how they navigate from unknown locations” says Associate Professor Kasper Thorup from the Center for Macroecology, Evolution and Climate.

Cuckoos are particularly suitable for navigation studies, as they lay their eggs inside the nests of other bird species. Growing up without contact to siblings or biological parents, the young cuckoo has no one to follow during migration. Flying alone and at night, it relies entirely on instincts, inherent abilities and the experiences gained later in life. Now, scientists can conclude that these traits are combined into a complex individual decision making strategy.

The study is published in Scientific Reports.  Science Daily  Original web page at Science Daily


To feed or not to feed: Researchers engage citizen scientists in reducing bird-window collisions

Getting in touch with nature in an urbanized world can be as simple as putting a bird feeder in your backyard. However, what are the potential consequences of this act? Bird-window collisions are one of the largest threats facing urban bird populations in Canada. A new study out of the University of Alberta engages citizen scientists to determine the effects of feeders on bird-window collisions.

Despite the popularity of feeding wild birds, the effects of bird feeders and year-round feeding on birds have not been well documented, particularly in relationship to bird-window collisions. “Backyard bird feeders create an important link between humans and nature,” says Justine Kummer, a graduate student at the University of Alberta and lead author of the study, the first ever to manipulate bird feeders at actual residential houses. “Improving the relationship between the general public and nature can promote biodiversity and conservation. We are working to find successful ways to reduce bird-window collisions, beneficial not only for birds but also for the millions of people who feed them.”

In Canada, it is estimated that up to 42 million birds die each year from collisions with windows, with residential homes accounting for 90% of building-related mortality. Trials were conducted on 55 windows at 43 residences in Edmonton and the surrounding area. Homeowners were asked to search their study window daily for evidence of bird-window collisions. Though there were 94 reported collisions with the presence of a bird feeder, there were also 51 collisions in cases when no feeder was present, meaning there is no black and white answer. Twenty-six of the windows never experienced a collision during the study, showing that some houses are more at risk than others, regardless of the presence of the feeder.

“We’ve determined that the presence of a bird feeder does indicate collision risk, but there are other factors involved,” says Kummer. She notes that vegetation and house characteristics can also influence whether a residence is likely to have a large number of collisions. “The general public enjoys feeding birds in their yard, but they want to know how to do so safely. Homeowners can certainly reduce some window collision risk by altering feeder placement.”

The study builds on previous work at the University of Alberta, well known for its conservation and biodiversity efforts. The paper was co-authored by Kummer’s graduate supervisor Erin Bayne, associate professor in biological sciences at the University of Alberta. Bayne’s research team focuses on understanding the cumulative ecological impacts of human activities on biodiversity.

The findings, “Bird feeders and their effects on bird-window collisions at residential houses,” were published this fall in the journal Avian Conservation and Ecology.  Science Daily  Original web page at Science Daily


* Hummingbirds rely on raw power, not physique, to outmaneuver rivals

Brute strength is surprisingly important to the ability of hummingbirds to outmaneuver rivals for nectar and evade predators, according to new University of British Columbia research published in eLife. An intensive study of 20 Anna’s hummingbirds, Calypte anna, led by the University of British Columbia, revealed that birds with the highest muscle capacity are able to accelerate faster and make more demanding, complex turns.

“We had expected wing morphology and body mass to have more of an influence on maneuverability so were surprised that muscle capacity is so important,” says Doug Altshuler, lead author from the University of British Columbia.

The scientists will repeat the experiments with other tropical species that have greater variation in body mass and wing morphology. These field studies will help determine whether the findings are common to other hummingbirds.

The muscle capacity of the birds was determined by attaching a necklace of weighted beads to each bird. Hummingbirds are able to fly directly upwards, and their maximum weight-lifting ability could be measured by how many of the beads they were able to lift. A two-hour solo flight of each bird was filmed to record and analyse their aerial displays.

For hummingbirds, the burst capacity of their muscles has an important evolutionary function. Their natural escape response is to fly vertically. They might need to employ this while hovering at a flower to feed. So, in addition to the power needed to hover normally, they need a reserve of power to accelerate away from predators or competitors. Competition within species can be severe, with birds defending a patch of individual flowers for access to nectar and often using their bills as daggers to stab other birds in flight.

Such airborne combat could explain why the birds in the study deployed some extra dazzling moves when paired. These competition trials, filmed over an additional two hours, involved chases, displacements and aerial displays but very little direct contact. Paired birds were found to use more arcing turns than pitch-roll turns in the presence of a competitor. Pitch-roll turns require the birds to slow down, which may make them a target for aggression by a competitor. The scientists believe they prefer arcing terms during competition so that they are always on the move when in flight.

They had expected to see even greater effects of competition, such as higher acceleration. However, they found that the paired birds actually accelerated more slowly during horizontal flight. This may be a result of the experiment being carried out in a chamber rather than in the wild. The benefit of this approach is that a large number of measurements from the same individuals can be combined with other data, allowing the new insights to be uncovered.  Science Daily  Original web page at Science Daily


Missing link between dinosaur nests and bird nests

The links between dinosaurs and birds keep getting stronger: skeletal structures, feathers—and now nests. Whereas some dinosaurs buried their eggs crocodile-style, a new analysis suggests that other dinosaurs built open nests on the ground, foreshadowing the nests of birds.

Interpreting the fossil record is always tough, but analyzing trace fossils such as nests is especially daunting. Those structures, and the materials used to make them, usually aren’t preserved, says Darla Zelenitsky, a paleobiologist at the University of Calgary in Canada. When paleontologists do find a nestlike structure that includes material such as sticks or other vegetation, the question arises: Was this stuff part of the original nest, or just carried there with the sediment that buried the nest and helped preserve it?

To gain insight into dinosaur nesting habits, Zelenitsky and her colleagues studied the most durable parts of nests—the eggs themselves. (Being largely made of the mineral calcium carbonate, they’ve got a head start on fossilization and are sometimes incredibly well preserved.) In particular, the team looked at the size and arrangement of small pores in the ancient shells, because those details are telling in modern creatures.

In crocodiles’ buried nests, the heat needed to incubate the eggs comes from decomposition of overlying organic matter or the sunlight absorbed by the soil. Plus, in buried nests airflow is somewhat limited, thus requiring eggs to be relatively porous to help increase the flow of oxygen into and carbon dioxide out of the eggs. But birds that brood in open nests can get by laying eggs with fewer or smaller pores.

So the team compared the porosity of eggshells from 29 species of dinosaurs (including large, long-necked herbivores called sauropods; bipedal meat-eaters called theropods; and duck-billed dinosaurs) with that of shells from 127 living species of birds and crocodiles

Most of the dinosaur eggs were highly porous, suggesting that they buried their eggs to incubate them, the researchers report online today in PLOS ONE. But some of the dinosaur species in one group—a subset of well-evolved theropods considered to be the closest relatives of modern-day birds—laid low-porosity eggs, which suggests they incubated their eggs in open nests.

“This is a well done paper; the results make a lot of sense,” says Luis Chiappe, a vertebrate paleontologist at the Natural History Museum of Los Angeles County in California. The findings, he says, line up other studies suggesting that some birdlike dinosaurs were warm-blooded, which would have enabled them to incubate eggs in an open nest rather than depend on rotting vegetation or sunlight. Chiappe adds that the trend toward open nests could have allowed some dinosaurs to take another step toward birdlike nesting by moving their nests into the trees.

But considering only two types of nests—open versus buried—may be too simplistic, suggests Anthony Martin, a paleontologist at Emory University in Atlanta. Some dinosaurs—like a few of today’s birds—may have nested in burrows, which could have offered the stable temperature and protection from predators of a buried nest but resulted in low-porosity shells. Also, covered nests come in different types: Loose vegetation piled atop a buried nest can have a lot of airflow through it, allowing eggs to have relatively small pores, whereas eggs buried in soil or similar materials might not breathe as well and thus require larger pores, he notes. Nevertheless, Martin adds, the team’s study “is a good first start toward answering the question about what early dinosaur nests looked like.”  Science Magazine  Original web page at Science Magazine


West Nile virus killing millions more birds than previously thought

Many people remember the arrival of West Nile in North America in 1999, if only because the initial outbreak killed not just wild crows but also exotic birds in the Bronx Zoo. In the following years, a trail of dead crows marked the spread of the virus from the East through the Midwest on to the West Coast. It took only four years for the introduced virus to span the continent.

But what happened to bird populations in the wake of the virus’s advance? Were some species decimated and others left untouched? After the initial die-off were the remaining birds immune, or mown down by successive waves of the disease? Nobody really knew.

Now, a study published in the Nov. 2 issue of Proceedings of the National Academy of Sciences provides some answers. The study, a collaboration among scientists at Colorado State University, the University of California at Los Angeles, Washington University in St. Louis and the Institute for Bird Populations (IBP), is the first to fully document the demographic impacts of West Nile virus on North American bird populations.

The scientists analyzed 16 years of mark-recapture data collected at more than 500 bird-banding stations operated using the Monitoring Avian Productivity and Survival protocol developed by IBP, a California-based nonprofit that studies declines in bird populations.

They discovered large-scale declines in roughly half of the species they studied, a much higher fraction than spot checks like the Christmas bird count had found. “Clearly we didn’t see the whole picture,” said Joseph A. LaManna, PhD, Tyson postdoctoral researcher in the Department of Biology in Arts & Sciences at Washington University. “It wasn’t just the jays that were dying; half the species we studied had significant die-offs.”

The data also revealed, however, that some species fared much better than others. Roughly half of the afflicted species managed to rebound within a year or two. Ironically, the resilient ones include the crows and other corvids who were so strongly associated with the disease on its arrival.

But a second group of birds, including Swainson’s thrush, the purple finch and tufted titmouse were not so lucky. Knocked down by the arrival of West Nile virus, they have not rebounded and seem to have suffered long-term population declines.

“Many more species of birds than we thought are susceptible to this virus,” said T. Luke George, PhD, an ecologist at Colorado State University. “And we also found long-term effects on population growth rates. Prior to this study, we generally thought the West Nile virus had a very short-term effect on bird survival.”

The scientists aren’t sure why some species fare better than others. Was a common evolutionary history predictive? Or similar habitats or diets? “That’s really the question our study opens,” said Ryan J. Harrigan, a biologist at the University of California, Los Angeles. “In the end, we’re not completely sure why some species recovered from this disease and some did not. That would be the next step forward, addressing that question.”

“The deeper story is that without long-term monitoring and detailed data, we miss patterns like these,” LaManna said. “Deaths in one area can be easily masked by immigration from other areas, and we wouldn’t really notice unless we happened to be looking at the right type of data. “This year was another big West Nile year,” LaManna said. “Most people don’t even know that.”   Science Daily  Original web page at Science Daily


Births down and deaths up in Gulf dolphins

A NOAA-led team of scientists is reporting a high rate of reproductive failure in dolphins exposed to oil from the Deepwater Horizon spill. The team has monitored these bottlenose dolphins in heavily-oiled Barataria Bay for five years following the spill. Their findings, published in Proceedings of the Royal Society today, suggest that the effects of the Deepwater Horizon oil spill will be long-lasting.

The study assessed reproductive success and survival rate for Barataria Bay dolphins. These dolphins had been sampled for health assessments in 2011, and were found to have a high prevalence of lung disease and adrenal dysfunction. Now the team is reporting that only 20% of the sampled dolphins that were pregnant produced viable calves. This is compared to a previously-reported pregnancy success rate of 83% from a similar study in a dolphin population in Sarasota Bay, which was not affected by the spill.

After nearly four years of monitoring, scientists were also able to estimate the survival rate of the dolphins sampled in 2011. They found that only 86.8% of the dolphins survived each year, as compared to other populations where roughly 95% of the dolphins survived. The reduced reproductive potential, along with decreased survival, will have long-term consequences for the Barataria Bay dolphin population.

In August of 2011, a team of independent and NOAA scientists evaluating the health of bottlenose dolphins in Louisiana’s Barataria Bay gave dolphin Y35 a good health outlook. Based on the ultrasound, she was in the early stages of pregnancy, but unlike many of the other dolphins examined that summer day, Y35 was in pretty good shape. She wasn’t extremely underweight or suffering from moderate-to-severe lung disease, conditions connected to exposure to Deepwater Horizon oil in the heavily impacted Barataria Bay.

Veterinarians did note, however, that she had alarmingly low levels of important stress hormones responsible for behaviors such as the fight-or-flight response. Normal levels of these hormones help animals cope with stressful situations. This rare condition–known as hypoadrenocorticism–had never been reported before in dolphins, which is why it was not used for Y35 and the other dolphins’ health prognoses.

Less than six months later, researchers spotted Y35 for the last time. It was only 16 days before her expected due date. She and her calf are now both presumed dead, a disturbingly common trend among the bottlenose dolphins that call Barataria Bay their year-round home.

This trend of reproductive failure and death in Gulf dolphins over five years of monitoring after the 2010 Deepwater Horizon oil spill is outlined in a November 2015 study led by NOAA and published in the peer-reviewed journal Proceedings of the Royal Society.

Of the 10 Barataria Bay dolphins confirmed to be pregnant during the 2011 health assessment, only two successfully gave birth to calves that have survived. This unusually low rate of reproductive success–only 20%–stands in contrast to the 83% success rate in the generally healthier dolphins being studied in Florida’s Sarasota Bay, an area not affected by Deepwater Horizon oil.

While hypoadrenocorticism had not been documented previously in dolphins, it has been found in humans. In human mothers with this condition, pregnancy and birth–stressful and risky enough conditions on their own–can be life-threatening for both mother and child when left untreated. Wild dolphins with this condition would be in a similar situation.

Mink exposed to oil in an experiment ended up exhibiting very low levels of stress hormones, while sea otters exposed to the Exxon Valdez oil spill experienced high rates of failed pregnancies and pup death. These cases are akin to what scientists have observed in the dolphins of Barataria Bay after the Deepwater Horizon oil spill.

Among the pregnant dolphins being monitored in this study, at least two lost their calves before giving birth. Veterinarians confirmed with ultrasound that one of these dolphins, Y31, was carrying a dead calf in utero during her 2011 exam. Another pregnant dolphin, Y01, did not successfully give birth in 2012, and was then seen pushing a dead newborn calf in 2013. Given that dolphins have a gestation of over 12 months, this means Y01 had two failed pregnancies in a row.

The other five dolphins to lose their calves after the Deepwater Horizon oil spill, excluding Y35, survived pregnancy themselves but were seen again and again in the months after their due dates without any young. Dolphin calves stick close to their mothers’ sides in the first two or three months after birth, indicating that these pregnant dolphins also had calves that did not survive.

At least half of the dolphins with failed pregnancies also suffered from moderate-to-severe lung disease, a symptom associated with exposure to petroleum products. The only two dolphins to give birth to healthy calves had relatively minor lung conditions.

Dolphin Y35 wasn’t the only one of the 32 dolphins being monitored in Barataria Bay to disappear in the months following her 2011 examination. Three others were never sighted again in the 15 straight surveys tracking these dolphins. Or rather, they were never seen again alive. One of them, Y12, was a 16-year-old adult male whose emaciated carcass washed up in Louisiana only a few weeks before the pregnant Y35 was last seen. In fact, the number of dolphins washing up dead in Barataria Bay from August 2010 through 2011 was the highest ever recorded for that area.

Survival rate in this group of dolphins was estimated at only 86%, down from the 95-96% survival seen in dolphin populations not in contact with Deepwater Horizon oil. The marshy maze of Barataria Bay falls squarely inside the footprint of the Deepwater Horizon oil spill, and its dolphins and others along the northern Gulf Coast have repeatedly been found to be sick and dying in historically high numbers. Considering how deadly this oil spill has been for Gulf bottlenose dolphins and their young, researchers expect recovery for these marine mammals to be a long time coming.   Science Daily  Original web page at Science Daily


Human handouts could be spreading disease from birds to people

People feeding white ibises at public parks are turning the normally independent birds into beggars, and now researchers at the University of Georgia say it might also be helping spread disease.

They recently launched a study to find out how being fed by humans is changing the health, ecology and behavior of white ibises in south Florida, where construction and land development is drying up their wetland habitats.

The birds normally feed on aquatic animals like fish, snails and crayfish, but they are now becoming accustomed to being fed items such as bread, fast food and popcorn by people at parks, said Sonia Hernandez, an associate professor with joint appointments in UGA’s Warnell School of Forestry and Natural Resources and College of Veterinary Medicine. This shift in feeding behavior could have serious consequences not just for the white ibises, she said, but also to people.

“In a previous study, and using molecular typing methods, we found that the strains of salmonella bacteria that white ibises are infected with are the same that some people get sick from, particularly in Florida,” Hernandez said. “Because white ibises move from urban to natural environments readily, they might be responsible for moving these strains around over large distances.”

Hernandez is working with other UGA researchers on the five-year, $2.1 million project, funded by the National Science Foundation’s Ecology and Evolution of Infectious Diseases Program. Their findings could apply to other wildlife species that have grown cozy with humans at public parks and other human-altered landscapes, she said.

Other researchers on the project are Jeff Hepinstall-Cymerman, an associate professor in the Warnell School; Sonia Altizer, a professor, and Richard Hall, an assistant research scientist, both in the Odum School of Ecology; and Kristen Navara, an associate professor in the College of Agricultural and Environmental Sciences.

The white ibis is most commonly found in Florida, although it can be spotted along the Atlantic coast as far north as North Carolina and on the Gulf Coast as far as Louisiana. They are normally nomadic, can travel for miles every day and typically spend much of their day searching for food.

But why expend energy searching for food when humans at public parks will give it to them, Altizer said. “If white ibises have a reliable food source, they might form larger flocks that stay put year-round near the parks.” This shift toward more sedentary behavior could allow pathogens transmitted through feces, like salmonella, to build up and pose risks for both birds and humans.

Greater numbers of ibises in urban parks also puts them contact with animals they wouldn’t normally meet in natural environments, like muscovy and mallard ducks, gulls and other common city birds — all reservoirs of diseases for birds.

As part of the project, the researchers will focus on white ibises in Palm Beach County, Florida, where Hernandez has been conducting field monitoring of the birds since 2010. The research site will span six urban and six natural areas in the county, and researchers will conduct field sampling of white ibises on a quarterly basis for two years to accurately estimate the birds’ population size.

They will put identification bands on the captured birds before releasing them, track movements using GPS devices, record basic data about each ibis marked, take blood samples and collect feces to determine salmonella infections.

Researchers are focusing on salmonella because it causes one of the most significant diarrheal diseases for people and can cause mortality in young wading birds.

“GPS technology is not just for humans anymore,” Hepinstall-Cymerman said. “We can now get up to 12 locations a day and for up to two years to understand how birds we capture at urban sites behave compared to birds caught at natural sites.”

If urban birds are roosting with birds that primarily use natural sites, diseases originating in urban areas could be spread throughout the white ibis population in Florida, he said. It doesn’t help that urbanized white ibises might also have weaker immune systems — most likely caused by contact with people, poor diets and stress from living in less-than-optimal environments.

“In fact, we are finding that urban ibises have extremely high levels of stress hormones and weak immune systems compared with other birds,” Navara said. “Ultimately, this could affect how pathogens, including salmonella, are being transmitted among individuals and between the birds and humans.”

Hall said it’s understandable that people would feed the friendly looking birds they see in parks — and it’s done with the best of intentions. However, researchers hope this project will raise awareness about how “helping” wildlife by feeding them can have unintended harmful effects.

“We also hope that these studies will inform good practices by which people can continue to enjoy encounters with wildlife in their backyards and cities, for example by developing good practices for bird feeder hygiene, what kinds of food to provide and knowing when to put up — and take down — feeders,” Hall said.  Science Daily  Original web page at Science Daily


Wild birds choose love over food

Wild birds will sacrifice access to food in order to stay close to their partner over the winter, according to a study by Oxford University researchers.

Scientists from the Department of Zoology found that mated pairs of great tits chose to prioritise their relationships over sustenance in a novel experiment that prevented couples from foraging in the same location. This also meant birds ended up spending a significant amount of time with their partners’ flock-mates. And, over time, the pairs may even have learned to cooperate to allow each other to scrounge from off-limits feeding stations.

The results, published in the journal Current Biology, demonstrate the importance of social relationships for wild birds — even when pursuing those relationships appears to be detrimental. Josh Firth, who led the research, said: ‘The choice to stay close to their partner over accessing food demonstrates how an individual bird’s decisions in the short term, which might appear sub-optimal, can actually be shaped around gaining the long-term benefits of maintaining their key relationships. For instance, great tits require a partner to be able to reproduce and raise their chicks.

‘Therefore, even in wild animals, an individual’s behaviour can be governed by aiming to accommodate the needs of those they are socially attached to.’

The research, which was carried out at Oxford University’s Wytham Woods site to the west of Oxford, involved the use of automated feeding stations with the ability to decide which individual birds could and could not access the food inside. Birds were allowed access based on radio frequency identification tags that were linked to the feeding stations.

In the experiment, mated pairs of birds were unable to access the same feeding stations as each other, meaning the male could only access the feeding stations that the female could not, and vice versa.

The researchers found that the birds randomly selected not to be allowed access to the same feeding stations as their partner spent significantly more time at feeders they could not access than birds that were allowed to feed together.

Josh Firth added: ‘Because these birds choose to stay with their partners, they also end up associating with their partners’ flock-mates, even if they wouldn’t usually associate with these individuals. This shows how the company an individual bird keeps may depend on their partner’s preferences as well as their own.

‘Also, when birds were going to feeding stations they couldn’t access because their mate was there, they learned over time to “scrounge” from those feeders by taking advantage of the fact the feeders remained unlocked for two seconds after recognising a bird’s identification tag. Interestingly, a relatively large amount of this scrounging was enabled by the bird’s own partner unlocking the feeding station, suggesting it may be a cooperative strategy.’  Science Daily  Original web page at Science Dail


* Vulture’s scavenging secrets: Ironclad stomach, strong immune system

Vultures have a unique genetic make-up allowing them to digest carcasses and guard themselves against constant exposure to pathogens in their diet, according to the first Eurasian vulture genome published in the open access journal Genome Biology. The study also finds that this species of Asian vulture is more closely related to the North American bald eagle than previously thought.

The cinereous vulture or black vulture, Aegypius monachus, is the largest bird of prey, and an iconic bird in the Far East. The species plays a key role in the ecosystem by removing rotting carcasses, thus preventing the spread of disease.

As their feeding habits involve constant exposure to pathogens, vultures are suspected to have strong immune systems, having evolved mechanisms to prevent infection by the microbes found in their diet. Despite the potential interest in the immune system of scavengers, little is known about the genetic variations involved in vultures’ immune processes.

Lead author Jong Bhak from Ulsan National Institute of Science and Technology, South Korea, said: “This is the first Old World vulture genome that has been reported, and we can see that the cinereous vulture has genetic signatures for resisting infection from eating decaying flesh. Understanding the genetic make-up of extreme life forms has potential for improving human health. The immune system genes we’ve identified could be useful targets in humans for protection against infection.”

The team sequenced the genome of a cinereous vulture, and compared it to that of the closely-related bald eagle, the national bird of the United States, to find genetic signatures of the dietary and environmental adaptations that help enable the vulture’s scavenging lifestyle.

Specifically, they found variations in genes related to the regulation of gastric acid secretion, consistent with their ability to digest carcasses. Other genetic variations included several in genes associated with immunity and defense against microbial and viral infections.

These included genes that allow cells to take up microorganisms and target pathogens for ingestion and elimination. The authors suggest that these may play a role in helping the vulture species combat pathogens encountered in their diet and complement the role of gastric secretion.

The term vulture refers to two groups of birds of prey that evolved independently, namely the Old World vultures, found in Africa, Asia and Europe, and the New World vultures, found in the Americas.

By analyzing its full genome, the researchers calculated that the Old World cinereous vulture species diverged from the North American bald eagle species around 18 million years ago. This split is much more recent than the divergence of the Old World and New World vultures around 60 million years ago. The results therefore add further evidence to the hypothesis that the two groups of vultures evolved their similar features and lifestyle independently in different locations.  Science Daily  Original web page at Science Daily


Secret nocturnal lives of wood thrushes

We know surprisingly little about what songbirds do after the sun goes down, but past studies have provided tantalizing hints that many forest birds roost for the night in different habitat from where they spend the day. A new paper confirms that wood thrushes often move out of their daytime ranges to sleep, seeking dense areas of vegetation where they’re safe from predators. We know surprisingly little about what songbirds do after the sun goes down, but past studies have provided tantalizing hints that many forest birds roost for the night in different habitat from where they spend the day. For a study forthcoming in The Auk: Ornithological Advances, Vitek Jirinec of the College of William and Mary and his colleagues captured and radio-tagged Wood Thrushes (Hylocichla mustelina) to track their movements during both day and night. Their results, the first broad description of roosting ecology for a migratory North American songbird during breeding season, show that the birds often move out of their daytime ranges to sleep, seeking dense areas of vegetation where they’re safe from predators.

Jirinec and his colleagues tracked 47 birds on the coastal plain of southeastern Virginia during the breeding seasons of 2013 and 2014, including 37 males and 10 of their mates. They found that males were not faithful to particular roosting spots, regularly moving from night to night, and overall one third of the roosting locations were completely outside the birds’ daytime ranges. Remote sensing data showed that those nighttime roosts were located in areas with higher-than-average canopy density, and the researchers suggest that the birds could have been making these commutes in order to roost in safer sleeping spots, where they would be well-hidden from predators.

Add nests into the mix and things become even more interesting. Nesting females spent the night in the nest cup–not surprising, since female Wood Thrushes are exclusively responsible for incubating eggs and nestlings. While nests were active, males didn’t stick around at night, continuing their usual routine of moving to safer roosting spots that were often outside their daytime territories. However, once a nesting attempt ended (either because the nestlings reached independence or because they were killed by a predator) males roosted side-by-side with their mates, inside their daytime range. Rather than being motivated by romance or loyalty, males were probably guarding their mates to prevent other males from surreptitiously mating with them in the dark.

Tracking birds at night led to some adventures. “Thankfully many of our study birds were in large forest tracks or chose not to roost near human dwellings, but there were still a considerable number of individuals who did just that,” says Jirinec. “Although I had the necessary permits, explaining that to homeowners at 2 a.m. after they spotted a guy creeping around their property, antenna at hand, was not what I was about to try. Therefore, in those instances, I followed the radio signal entirely in the dark, feeling my way around the forest very slowly and turning on my headlamp only at the last instance to confirm bird position, then quickly absconding with my precious roosting data as newspaper headlines like ‘Graduate student shot in the buttocks by Colonial Williamsburg resident’ swirled in my mind.”

“This is an important study that uses robust data collection from extensive radio-tracking to answer a simple question that has important conservation implications: how often do Neotropical migrants use different habitats for roosting and day-time activity on their breeding grounds?” adds Kara Belinsky of the State University of New York, New Paltz, an expert on the behavior and ecology of thrushes. “The use of different roost habitat should inform conservation plans for this declining species–we will need to protect high-quality roosting habitat as well as high-quality nesting and daytime habitat if we want to slow the decline of this species, and the same is also likely to be true for many of the other Neotropical migrants we care about.”   Science Daily  Original we page at Science Daily


Growing up without parents makes endangered birds more flexible

This is it, kids: official permission to stop listening to what your parents tell you–but only if you’re a bird. Many animal parents spend time teaching their young about how to find food and avoid danger, and this usually gives a big boost to their offspring. In a Commentary forthcoming in The Condor: Ornithological Applications, however, Vladimir Dinets of Louisiana State University makes the case that when environmental conditions change, relying on their parents’ way of doing things can actually hinder, not help, young cranes.

Only one remaining population of Whooping Cranes is completely descended from wild birds raised by their parents. On both their breeding grounds in Canada and their wintering grounds in Texas, they’re very picky about what habitat they use, sticking to a certain type of wetland, and each generation teaches its young to do the same; historically, this type of habitat must be where they’ve had the most success. However, when captive-reared Whooping Cranes, free of their parents’ hang-ups, were released in Louisiana, they moved into a wide variety of human-modified habitats like agricultural fields and suburban ponds, and their flexibility has helped them succeed.

“Many animals learn some of their behavior, such as avoiding humans and choosing the right habitat, from their parents. This learning is called ‘cultural transmission of behavior.’ Usually it’s a good thing for the young,” explains Dinets. “But in our rapidly changing world, this learning of ‘traditional’ behavior can make the young animals less adaptable, for example, if they have to survive in human-modified habitats with lots of human disturbance. Animals that learn to survive by themselves, without parental guidance, might do better in such places, as illustrated by the success of the Whooping Crane reintroduction program in Louisiana.”

The Commentary goes on to describe similar results from captive-raised, reintroduced populations of storks in Japan, ibises in Spain, and geese in Hawaii–again and again, birds raised without their parents’ guidance don’t share their ancestors’ reluctance to forage and nest near humans. “Dinets challenges managers of reintroduction programs to reconsider the effects of pre-release management techniques,” adds George Archibald, co-founder of the International Crane Foundation. “This wide-ranging description of the results from an array of species will help researchers ponder future directions. As someone involved in the study of the restoration of crane populations via captive management and releases, I am acutely aware of the complexities of avian behavior and of the need for continual improvement of practices.”  Science Daily  Original web page at Science Daily


* Antiviral compound provides full protection from Ebola virus in nonhuman primates

Rhesus monkeys were completely protected from the deadly Ebola virus when treated three days after infection with a compound that blocks the virus’s ability to replicate. These encouraging preclinical results suggest the compound, known as GS-5734, should be further developed as a potential treatment, according to research findings to be presented tomorrow at the IDWeek conference.

Travis Warren, Ph.D., a principal investigator at the U.S. Army Medical Research Institute of Infectious Diseases (USAMRIID), said the work is a result of the continuing collaboration between USAMRIID and Gilead Sciences of Foster City, Calif. Scientists at the Centers for Disease Control and Prevention (CDC) also contributed by performing initial screening of the Gilead Sciences compound library to find molecules with promising antiviral activity.

The initial work identified the precursor to GS-5734, a small-molecule antiviral agent, which led to the effort by Gilead and USAMRIID to further refine, develop and evaluate the compound. Led by USAMRIID Science Director Sina Bavari, Ph.D., the research team used cell culture and animal models to assess the compound’s efficacy against several pathogens, including Ebola virus.

In animal studies, treatment initiated on day 3 post-infection with Ebola virus resulted in 100 percent survival of the monkeys. They also exhibited a substantial reduction in viral load and a marked decrease in the physical signs of disease, including internal bleeding and tissue damage.

“The compound, which is a novel nucleotide analog prodrug, works by blocking the viral RNA replication process,” said Warren. “If the virus can’t make copies of itself, the body’s immune system has time to take over and fight off the infection.”

In cell culture studies, GS-5734 was active against a broad spectrum of viral pathogens. These included Lassa virus, Middle East Respiratory Syndrome (MERS) virus, Marburg virus, and multiple variants of Ebola virus, including the Makona strain causing the most recent outbreak in West Africa.

“This is the first example of a small molecule–which can be easily prepared and made on a large scale–that shows substantive post-exposure protection against Ebola virus in nonhuman primates,” Bavari commented. “In addition to 100 percent survival in treated animals, the profound suppression of viral replication greatly reduced the severe clinical signs of disease.”

Taken together, the robust therapeutic efficacy observed in primates and the potential for broad-spectrum antiviral activity suggest that further development of GS-5734 for the treatment of Ebola virus and other viral infections is warranted, Bavari said.

According to Tomas Cihlar, Ph.D., of Gilead Sciences, the company is currently conducting phase I clinical studies of the compound in healthy human volunteers to establish the safety and pharmacokinetic profile.

“We are exploring alternative directions for developing this compound, including potential use of the animal efficacy rule,” Cihlar said, referring to a regulatory mechanism under which the U.S. Food and Drug Administration may consider efficacy findings from adequate and well-controlled animal studies of a drug in cases where it is not feasible or ethical to conduct human trials.

Ebola virus causes severe hemorrhagic fever in humans and nonhuman primates with high mortality rates and continues to emerge in new geographic locations, including West Africa, the site of the largest outbreak to date. Over 28,000 confirmed, probable and suspected cases have been reported in Guinea, Liberia and Sierra Leone, with over 11,000 reported deaths, according to the World Health Organization. Although several clinical trials are currently underway, there are no licensed vaccines or therapies against Ebola virus.

Research on Ebola virus is conducted in Biosafety Level 4 (maximum containment) laboratories, where investigators wear positive-pressure “space suits” and breathe filtered air as they work. USAMRIID is the only organization in the Department of Defense with Biosafety Level 4 capabilities, and its research benefits both military personnel and civilians.

Presentation: “Nucleotide Prodrug GS-5734 Is a Broad-Spectrum Filovirus Inhibitor that Provides Complete Therapeutic Protection Against Ebola Virus Disease in Infected Non-human Primates.”  Science Daily  Original web page at Science Daily


From hummingbird to owl: New research decodes bird family tree

The rapid extinction of dinosaurs 65 million years ago gave rise to a stunning variety of bird species over the next few million years, according to Florida State University researchers.

A study published in the journal Nature in coordination with Yale University resolved the bird family tree, something that has never been accomplished by scientists. It shows that all land birds diverged early on from a group that includes vultures and hawks, and indeed that all birds evolved from a group of dinosaurs that included the Tyrannosaurus rex and Velociraptor.

“These birds just diversified rapidly after dinosaurs went extinct,” said Emily Moriarty Lemmon, assistant professor in the Department of Biological Science at FSU. “Now that these relationships have been identified, we can more accurately study how color vision, feather structure and many other bird traits have evolved through time. ”

The researchers also showed that owls are closely related to toucans and hornbills and that falcons are closely related to parrots and songbirds. The study also confirmed that a nocturnal nightjar — a bird with long wings, short legs and very short bills — is related to the tiny and colorful hummingbird.

Birds are the only living descendants of dinosaurs. But until now, scientists really had no idea how quickly they had spun off into different species. In fact, after dinosaurs died out, more than 10,000 bird species evolved in only a few million years.

In addition to showing the relationships between land birds, researchers also found that it was very rare for early bird species to change between terrestrial and aquatic lifestyles. Researchers concluded that nearly all water-based birds, such as penguins, pelicans and gulls, shared a common ancestor.

Scientists were able to complete this family tree because of a genetic sampling technique developed by Alan and Emily Lemmon at FSU’s Center for Anchored Phylogenomics. The technique targets a few hundred key locations on each genome — there are thousands of genes in the full genome — that are present in all of the species and contain sufficient DNA sequence variation to uncover the relationships among organisms.

Past attempts to build a full family tree, or phylogeny, for birds have been only partially successful. Other scientists have attempted to do so by using the full genomic sequence for a few dozen birds, which is both time consuming and extremely expensive.

The Lemmons and their collaborators, in contrast, analyzed several hundred genes for four times the number of bird species at a fraction of the cost of the previous study and successfully uncovered the bird family tree.

“There is so much diversity in birds that you have to look at a large number of species to really get a clear picture,” said Alan Lemmon, associate professor of scientific computing.  Science Daily  Original web page at Science Daily


Pathogen-carrying neotropical ticks ride migratory birds into US

Tick species not normally present in the United States are arriving here on migratory birds. Some of these ticks carry disease-causing Ricksettia species, and some of those species are exotic to the US. The research is published on October 2nd in Applied and Environmental Microbiology, a journal of the American Society for Microbiology.

In the study, the investigators examined thousands of migratory birds that had just arrived in the US, after having flown from Central or South America. Three percent of the birds carried exotic ticks. Based on the total number of migratory birds arriving in the US each spring–in the billions–the investigators estimated that more than 19 million exotic ticks are introduced into the US each spring, said Emily B. Cohen, PhD, Postdoctoral Fellow, Migratory Bird Center, Smithsonian Conservation Biology Institute, National Zoological Park, Washington, DC.

But as yet there is no evidence that neotropical ticks have established themselves in the US. “It takes the right combination of biotic and abiotic features for the neotropical ticks to survive, reproduce and spread,” said Sarah A. Hamer, PhD, DVM, Assistant Professor in the Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University. The ticks typically take their first and second blood meals on birds, but once they become adults, they seek out large mammals such as sloths or anteaters, she explained, noting the absence of these exotic mammals from the US.

“Nonetheless, an adult of one of the neotropical tick species we found on migrants, Amblymma longirostre, was recently found crawling outside of a home in Oklahoma, in the fall, which could represent a bird-imported nymph that arrived in the spring and successfully molted,” said Cohen.

Moreover, there is precedent for implicating migratory birds in range expansions of ticks and disease. For example, the range of African bont ticks and the livestock-infecting bacterial species they carry, Ehrlichia ruminatium, expanded to the Caribbean, probably after the ticks hitched a ride on migratory cattle egrets. E. ruminantium, causes heartwater disease, which reduces livestock productivity. Also, migratory birds are responsible for expanding populations of Lyme disease ticks beyond their northern distribution limit, in Canada.

The more general danger, said Cohen, is that the changing climate, or changes in other environmental conditions, could change the ranges of potential hosts of ticks, in ways that could enable the ticks to establish themselves. She recommended that studies should be undertaken to assess the likelihood of such an occurrence. Hamer has begun to examine diverse wild mammals for neotropical ticks, including rodents, raccoons, coyotes, and feral hogs, which are abundant across Texas.  Science Daily  Original web page at Science Daily


Invasive brood parasites a threat to native bird species

North Americans might be seeing new species of birds in certain areas of the continent in the near future. According to research conducted by a psychology professor at the University of Tennessee, Knoxville, and his co-authors, Eurasian birds are beginning to develop a presence on our continent, which could end up having a negative effect on native species.

Vladimir Dinets, research assistant professor of psychology, recently published a paper in the Journal of Field Ornithology examining the threats of global warming and its effects on wild animals. The warming climate is allowing various species in North America and Eurasia to get closer to, and even cross, the Bering Strait, a natural barrier only 50 miles wide. Birds from Eurasia, in particular, are crossing into North America.

Dinets, who has traveled extensively on both sides of the Bering Strait, notes that in the past 20 years, the vegetation of the region has changed dramatically. What used to be hundreds of miles of open tundra is now dense shrubland. And more southern bird species use this change to colonize new areas. For example, the savanna sparrow has recently begun breeding in Siberia, while the great spotted woodpecker has made it to Alaska for the first time.

Along with Mark Hauber, professor of neurobiology and behavior at City University of New York, and their co-authors, Dinets has discovered that two species of Eurasian cuckoos are on the verge of invading North America, and one of them may already be breeding here. These birds are considered brood parasites because they lay eggs into the nests of other birds and throw out the host’s eggs to ensure there is no competition for food from the adoptive parents.

If these cuckoos become established in North America, the native bird population will decrease as a result. Some North American birds have evolved defenses against cowbirds, which are native brood parasites. But through their research, Dinets and Hauber have found that these defenses are likely to fail against the invasive cuckoos because cuckoos are more sophisticated parasites: for example, they can mimic the egg color of their hosts.

While the Eurasian cuckoos are threatening to invade North America, American cowbirds are increasing their presence in Eurasia. Many Eurasian birds have evolved defenses against cuckoos, but cowbirds are less picky about choosing their hosts, and might threaten other species that are not parasitized by cuckoos and have no defenses.

Dinets and Hauber are proposing to start monitoring when and where the invading cuckoos begin to breed in North America. They believe the foothold area will most likely be western Alaska, where a small number of people interested in birds are spread out over a large territory.

Dinets added that local fish and wildlife authorities, hunters and other people spending a lot of time outdoors should be taught to recognize Eurasian cuckoos in order to mitigate the effects when the cuckoos arrive. “It is important to predict which native species are most at risk and to monitor their populations so that if they start to decline catastrophically, we can establish captive breeding programs and other supportive measures,” he said.  Science Daily  Original web page at Science Daily


* ‘Immune camouflage’ may explain H7N9 influenza vaccine failure

The avian influenza A (H7N9) virus has been a major concern since the first outbreak in China in 2013. Due to its high rate of lethality and pandemic potential, H7N9 vaccine development has become a priority for public health officials. However, candidate vaccines have failed to elicit the strong immune responses necessary to protect from infection. A study published in Human Vaccines & Immunotherapeutics has revealed that it may be due to immune camouflage

One of the ways by which the immune system detects infection is by presenting short peptides derived from the pathogen to T-cells, which distinguish between foreign and self antigens. The study shows that the H7N9 hemagglutinin (HA) surface protein has evolved a set of mutations that make it similar to human proteins, and the presented peptides thus resemble self antigens. The H7N9 influenza strain appears to effectively camouflage itself from the immune system.

“The original observation of low H7N9 T-cell epitope content was made before any data were available on vaccine efficacy,” says senior author Prof. Anne S. De Groot, Director of the Institute for Immunology and Informatics at the University of Rhode Island and CEO at EpiVax, Inc. “It turns out that we were absolutely correct. By comparison with H1N1 and H3N1, H7N9 vaccines are far less immunogenic.”

Prof. De Groot’s research team has developed a computational tool, JanusMatrix, capable of determining whether a given viral protein is similar to any human protein in residues relevant for antigen presentation.

“JanusMatrix looks at both ‘faces’ of T-cell epitopes. It starts by looking at the face that binds to HLA or MHC — the downward facing amino acids that bind into the MHC binding pockets. Having determined that a peptide can bind to a specific MHC, the program then looks at the T-cell receptor face (TCR face) and looks in a database of pre-parsed peptides from the human genome that have been identified as binding to the same MHC, for peptides that have the same TCR-facing amino acids.”

It turns out that, in addition to having low T-cell epitope content, HA from H7N9, but not from other investigated influenza strains, shows high similarity to several endogenous proteins.

The immune-camouflage hypothesis was tested by challenging peripheral blood mononuclear cells from naïve donors with H7N9-derived peptides. Remarkably, the more the peptide resembled a self antigen, the less it was able to elicit a T-cell response. In addition, the predicted human-like antigens expanded and activated regulatory T-cells that are responsible for immune suppression when endogenous peptides are presented, providing further support for the hypothesis.

“It appears that this new mechanism of immune escape may be common to quite a few human pathogens,” says Prof. De Groot. “We are working on validating several other peptides, some from common seasonal strains of influenza and some from pathogens like HIV and M. tuberculosis that do live for a long time inside their hosts.

H7N9 influenza has infected almost 670 people and led to 230 deaths, according to the U.S. Centers for Disease Control and Prevention. These findings could facilitate the development of an effective vaccine and impact vaccine research in general. “It could well explain why some candidate vaccines for pathogens that have co-evolved with human beings — like TB and HIV — do not work so well. It also suggests that ‘tweaking’ pathogen proteins to remove those camouflaging sequences would result in better, more effective vaccines,” concludes Prof. De Groot.  Science Daily  Original web page at Science Daily