Tag: Birds (pet; ornamental; prey e.g. falcons)

It can be challenging to develop a task setup to test inference by exclusion that can be applied in similar way to different species. One of the problems of previous studies was to exclude the possibility that animals chose a novel stimuli simply out of curiosity rather than by the exclusion of known negative stimuli. The use of the touchscreen presents a controlled setting to test cognitive capacities in animals and has already successfully been used in a number of species.

Goffin cockatoos are a highly curious Indonesian parrot species that have already proven to possess remarkable cognitive capacities. They possess high levels of ‘Neophilia’, which is the tendency of an individual to explore novel items and is believed to have evolved in species inhabiting islands, as there they might face fewer or no predators. In the current task, the Goffins had to learn to associate a picture with a reward that would be delivered automatically after they touched the picture on the touchscreen whereas the picture next to it would lead to no reward. During this training the unrewarded stimulus occasionally was replaced by novel, unknown stimuli. Only once the individuals chose reliably the positive stimulus over the negative or novel ones they were tested for their inference skills. This procedure ensured that the cockatoos would not choose novel pictures purely based on curiosity in the test.

In the following tests however, various combinations of novel and known pictures, which could be rewarded or unrewarded, were presented to the birds. Depending on how the individuals performed in this sequence of tests, allowed the researchers to tell apart other, strategies that may have used by the animals. “More than half of our cockatoos choose their pictures in a way that clearly indicates the ability of infer by exclusion about rewarded stimuli. However alternative strategies also play an important role in guided their choices,” says Mark O’Hara who developed this task together with his colleagues.

“Considering the cockatoos capacities in previous tasks we actually expected that they would show inferences by exclusion, but this was the first test if we could detect this ability with our new task. That we could show this sort of reasoning, together with other strategies so nicely, lets us hope that the method will be applicable to many species and ultimately might help us to understand something about the evolution of this ability” he adds.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/08/150826102032.htm  Original web page at Science Daily

Among our greatest achievements as humans, some might say, is our cumulative technological culture — the tool-using acumen that is passed from one generation to the next. As the implements we use on a daily basis are modified and refined over time, they seem to evolve right along with us.

A similar observation might be made regarding the New Caledonian crow, an extremely smart corvid and the only non-human species hypothesized to possess its own cumulative technological culture. How the birds transmit knowledge to each other is the focus of a study by Corina Logan, a junior research fellow at UC Santa Barbara’s Sage Center for the Study of the Mind when she conducted her research. Currently, she is a Leverhulme Early Career Research Fellow in the Department of Zoology at the University of Cambridge.

“We don’t know whether the crows have cumulative technological culture, and one of the reasons is that we don’t know how they learn,” said Logan. “There’s a hypothesis that says in order for cumulative technological culture to occur you need to copy the actions of another individual. And we don’t know whether the crows are paying attention to the actions of others when they learn from someone else.”

But the crows have been observed using tools they’ve made out of long, narrow, palm-like Pandanus leaves. “It has a serrated edge, and they cut into one side of the leaf, then make another cut farther down and then rip off the part in between,” Logan explained. “It makes a tool they can use to dig grubs out of logs.”

Even more curious, according to Logan, the crows have been observed using tools made of the same material but in different shapes — wide, narrow and stepped, which might be more structurally sound. However, no one has been able to explain the geographic variation in tool shapes — all three shapes are seen at the south end of New Caledonia, while the stepped tool is more prevalent everywhere else.

“It’s thought that in order for tool shapes to be transmitted, one bird would have to watch another cutting the leaf and then mimic that bird’s actions,” Logan continued. “That would require imitation or emulation.”

So Logan devised a study to look at all the learning mechanisms — social and asocial — the crows employ when solving a foraging problem. To level the playing field so that those birds with more experience with one particular tool don’t have an advantage over the others, Logan gave them a novel non-tool task.

She designed the experiment based on apparatus used by University of Leeds zoologist Will Hoppitt in a similar study he conducted on meerkats. “I used two apparatuses with multiple access points on each,” she said, “so we could look at whether the crows were imitating or emulating, whether they were just paying attention to another crow’s general location or whether they were paying attention to a specific area on an apparatus that another crow was interacting with.”

Logan and colleagues found that the crows don’t imitate or copy actions at all. “So there goes that theory,” she said. “Assuming how they learn in a non-tool context carries over to a tool context, they wouldn’t copy the actions of individuals they see cutting up Pandanus leaves to make tools.”

But Logan and her team did strong evidence of social learning: If one crow sees a companion interacting with a particular area of the apparatus, reaching its bill through a door and pulling out a piece of boiled egg — the treat — the former is far more likely to try that particular door on either apparatus before choosing the other access options.

“It’s called stimulus enhancement,” she explained. “That’s the social learning mechanism they’re using. But there’s another interesting aspect: Once they see another bird interact with the door, they go to that door and then begin to solve the problem on their own. And now they completely ignore social information and they just use trial and error learning to open the door and extract the food.”

Even if one crow is at an apparatus and tries unsuccessfully to open the door, if he or she sees another crow on the second apparatus actually solving the problem correctly, the first crow doesn’t use that information. “The social learning attracts them to a particular object and then they solve it through trial and error learning after that,” Logan said.

“So we thought, ‘Okay, if they don’t imitate or emulate, how could they still have cumulative technological culture?'” she continued. Perhaps it’s a combination of social learning and trial and error. Consider the grub digging. “In the wild, juveniles live with or near their parents for the first year or so,” she explained. “The juveniles see their parents make and use a particular tool shape. And often the parent will leave the tool inside the hole in the log and the juveniles will grab it and start interacting with it.

Similar to the stimulus enhancement Logan and her team identified initially, the crow parents could draw their children’s attention to the tools to make them more likely to interact with the tools. In addition, wild juveniles appear to learn how to use the tool through trial and error over the course of several months.

“We’re suggesting it could be that they’re copying the end result of another crow’s action, but they’re not copying the actual actions of the other crows,” Logan continued. “It’s actually a form of emulation but it doesn’t involve the copying actions that were hypothesized previously.”

For this study, Logan placed the crows in small groups. One was a family that consisted of two parents and their two sons; another included two mated pairs that weren’t related; and the third was made up of an adult and five juveniles. One of the juveniles was likely the adult’s daughter but the rest were unrelated. It had been previously hypothesized that juveniles do most of the learning, with adults picking up very little, if anything, from the youngsters or from each other

It turns out this was mistaken. “It didn’t matter what group it was,” Logan said. “Everyone learned from everyone — juveniles from juveniles, adults from adults, juveniles from adults, adults from juveniles. It seems that if they have the opportunity, they’ll learn from anyone. But because they live in family groups, it seems to constrain who they have the opportunity to learn from in the wild.”

Logan plans to replicate the study with the great-tailed grackle, another highly intelligent bird. “They are expanding their range really rapidly,” she said. “There are many questions about how they learn to forage so successfully in new environments. Are they learning from other species about what to forage on when they encounter a new food type? Or are they exploring on their own, using their own information?”

According to Logan, studies such as this broaden our understanding of the nature of cumulative technological culture. If it can spread through other mechanisms, such as stimulus enhancement — simply drawing one’s attention to something and imprinting on a particular way of doing things — it could expand scientists’ ideas about where they should look for cumulative culture in general, and cumulative technological culture in particular.

http://www.sciencedaily.com/  Science Dail

http://www.sciencedaily.com/releases/2015/08/150826113817.htm  Original web page at

Science Daily

Who actually enjoys long-haul flights? One seabird seems to – the ancient murrelet. It travels almost 8000 kilometres across the north Pacific, then does the whole slog again in reverse, for no obvious benefit. Most migrating birds travel long distances from north to south, or vice versa, to spend the harsher winter in warmer climates, often crossing the equator. Some travel from east to west, to areas where they can get more food.

But the ancient murrelet is unique, criss-crossing the Pacific to move between areas of similar climate. Some of them breed in western Canada and then winter in seas between Japan, China and Korea, before heading back to Canada – the only bird known to cross the full width of the North Pacific. The ancient murrelet is, Gaston says, a rather obscure and not well studied seabird. A member of the auk family, which also includes puffins and guillemots, it mainly breeds in the Haida Gwaii archipelago off the coast of British Columbia.

Gaston and his colleagues used geolocator tags to study the migration of ancient murrelets in 2013 and 2014. They managed to recover data from three of the geolocators and found that the birds had slowly crossed the North Pacific from July to November, travelling from Haida Gwaii to Japan. “I don’t know of any other bird that covers such a long distance from east to west,” says Gaston, “especially when it winds up in waters that are very similar to those it just left.”

Then in February, they set off back to Haida Gwaii, rapidly covering almost the whole distance within a month – the longest migration of any bird in the auk family. This is also twice as far as the longest cross-Atlantic migrations undertaken by Brünnich’s guillemot, which cover 70 degrees of latitude compared with murellets’ 105 degrees, Gaston’s team says. This means they travelled some 270 kilometres per day, probably flying 4 to 5 hours a day.

Gaston is not sure why their outward journey was slower, though he speculates it could be down to moulting hampering flight. There is no obvious reason for the birds to leave North American waters, which support many other seabirds over winter, for the equally temperate Japan. Genetic evidence suggests that the ancient murrelet originated from Asia and has only recently colonised North America, says Gaston. So the ancient murrelet could now be retracing the route by which the species colonised America from Asia. “There doesn’t seem to be any other suitable explanation,” Gaston says.

Journal reference: Ibis, DOI: 10.1111/ibi.12300

https://www.newscientist.com/  New Scientis

https://www.newscientist.com/article/dn28018-bird-flies-16000-kilometre-pacific-circuit-for-no-clear-reason/  Original web page at New Scientist

You might think that young children would first learn to recognize sounds and then learn how those categories of sounds fit together into words. But that isn’t how it works. Rather, kids learn sounds and words at the same time. In fact, the higher-level patterns — those words — are key in learning to recognize and place speech sounds into meaningful categories. That’s why children who grow up in Japanese-speaking homes don’t recognize the difference between ‘r’ and ‘l’ sounds. In Japanese, that distinction doesn’t matter. Now, researchers reporting in the Cell Press journal Current Biology on June 25 present evidence from European starlings showing that songbirds learn their songs in much the same way.

‘It wasn’t clear whether this kind of learning — where knowledge of a pattern informs understanding about the categories that make up the patterns — was unique to humans and language, or is a more general process shared with other animals,’ says Timothy Gentner of the University of California, San Diego. ‘We showed that this kind of learning is shared with, at least, songbirds. When birds learn to recognize patterns of song elements, they get a big boost in their ability to categorize those elements.’

Starlings’ songs consist of short, stereotyped patterns of simple notes grouped into ‘motifs’ and longer, well-defined sequences of motifs organized into bouts. Those motifs fall into one of four categories: whistles, warbles, rattles, or high frequencies. Gentner and his colleagues wanted to find out how patterns influence starlings in their ability to categorize those sounds.

Jordan Comins, a graduate student in Gentner’s lab and lead author of the study, trained four starlings to differentiate complex auditory patterns following the form AABB and BBAA from those that followed the form ABAB and BABA, where A and B denote natural motif categories of warbles and rattles. The researchers trained a second group in the same way, except that they shuffled the patterns.

The researchers found that the birds presented with clear patterns of sounds were at a big advantage over the other group in their ability to correctly categorize the motifs they’d heard. The findings show that songbirds rely on patterns in much the same way that people do. ‘We ‘hear’ words, not sequences of speech sounds,’ Gentner says. ‘While it is tempting to think that this is a uniquely human way of perceiving the world, it is not.’

Birds may not have language, but they still can teach us much about the biological and psychological mechanisms that make language and language learning possible, the researchers say. Having identified this basic form of shared top-down learning, Gentner’s team will now explore more subtle details of the perceptual categories and patterns in the birds to see how precisely they match human speech acquisition. They will also examine the extent to which pattern knowledge shapes the representation of complex vocal signals in the songbird brain.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/06/150625130900.htm  Original web page at Science Daily

Have you ever caught yourself yawning right after someone else did? The same happens to budgies, says Andrew Gallup of State University of New York in the US. His research team is the first to note that contagious yawning also occurs between members of a bird species. Thus far, it has only been known to happen with a few mammals. The results are published in Springer’s journal Animal Cognition.

Contagious yawning was previously thought only to occur between humans, domestic dogs, chimpanzees and a type of rodent aptly called the high-yawning Sprague-Dawley rat. “To date, this is the first experimental evidence of contagious yawning in a non-mammalian species,” says study leader Gallup. Budgies are of Australian origin and are often kept in cages as pets. The findings that contagious yawning occurs between budgerigars (Melopsittacus undulatus), also known as parakeets, in a controlled laboratory setting corroborate a previous observation of the same thing happening in a flock of these social parrots. In the wild, these birds form lasting bonds within breeding pairs and interact within coordinated flocks throughout the year. In a laboratory setting, budgies are known to automatically imitate video stimuli shown to them.

Gallup’s team conducted two experiments. In the first, 16 birds were paired in adjacent cages with and without barriers blocking their view. If contagious, yawns should be clustered in time only when the birds can see another. In the second experiment, the same birds were shown separate video clips of a budgie yawning and not yawning. Yawning was found to occur three times as often within a five-minute window when the birds could see one another than when their view was blocked from the other bird. When they were viewing video clips of another budgie yawning, yawns occurred twice as often. This response was not the result of stress or anxiety.

The researchers believe that contagious yawning is more than just an involuntary action, but is rather a primitive form of showing empathy. It has for instance been found that it is more common among people who are deemed to be more empathic. Thanks to a process called emotional contagion or state matching, contagious yawning occurs when a person thinks about or senses someone else carrying out this somewhat drowsy action.

Birds are known to have certain emphatic responses. Gallup therefore proposes that since contagious yawns can be experimentally manipulated, budgies could be used as a good model to explore other primitive forms of empathic processing in birds.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/05/150528083830.htm  Original web page at Science Daily

Mexican Jays (Aphelocoma wollweberi) distinguish between heavier and lighter peanuts without opening the nuts. The birds do it by shaking the nuts in their beaks, which allows them to ‘feel’ nut heaviness and to listen to sounds produced by peanuts during handling Mexican Jays (Aphelocoma wollweberi) handling peanut pods appear to evaluate the pod content by ‘weighing’ the pods and by ‘listening to’ them.

Many animals feed on seeds, acorns or nuts. The common feature of these are that they have shells and there is no direct way to know what’s inside. How do the animals know how much and what quality of food is hidden inside? A simple solution would be to break the shells, which often takes time and effort — it would be a big disappointment to know that it’s rotten or bad after the hard effort of opening the nuts! Can animals evaluate the food hidden inside the nuts? This is especially important for some animals who cache the food items for later use without opening and checking each item. We can detect which one is heavier by moving the items up and down several times and focusing on the “feeling of heaviness” we perceive. Humans can also detect the quality of a water melon by knocking on it.

A new study published in Journal of Ornithology suggests that some birds can also use similar tricks in choosing the peanuts from the feeder. Their study was carried out in Arizona by an international research team from Poland and Korea and revealed that the Mexican Jays (Aphelocoma wollweberi) may be able to “weigh” peanuts and maybe even “listen to” peanuts while handling them in their beaks. Drs. Sang-im Lee, Piotr Jablonski, Maciej and Elzbieta Fuszara, the leading researchers in this study, together with their students and helpers, spent many hours delicately opening shells of hundreds of peanuts, changing the contents and then presenting them to the jays in order to see if the birds can figure out the differences in the content of identically looking peanut pods (peanuts in shell).

“When we presented the jays with ten empty and ten full identically looking pods (pods without or with three nuts inside), we noticed that after picking them up the birds rejected the empty ones and accepted the full peanuts, without opening them.” says Dr. Sang-im Lee of Seoul National University — the corresponding author of the paper. A series of similar experiments with identically looking normal nuts and nuts that were 1g heavier (pods with some clay added) confirmed that jays always were able to distinguish and preferred the heavier nuts. How did they know which were empty without opening them? The researchers used slow motion videos to see what happens when the bird is deciding whether to drop or take away the peanut pod. “We found out that birds shake the nuts in their beaks. We think that these movements may provide them with the information generally similar to our feeling of “heaviness” when we handle an object in our hands,” says Dr. Jablonski.

In another experiment the researchers prepared one type of peanut pods by opening the shell, removing two out of the three nuts and closing the shell again. The second type of pod was prepared by opening a small pod, which normally contains only one nut, and closing it. Thus, the jays were to choose between nuts of similar content and mass but of different size. “The jays figured out that the larger pods did not weigh as much as they should and the birds preferred the smaller pods, which weighed as expected for their size,” comments Dr. Fuszara. They behaved as if they knew that “something is wrong” with the larger nuts.

So how do they know it? When they shake the nuts in their beaks, the birds produce sounds by opening and closing their beaks around the peanut shell for brief moments. The researchers think that the jays also take this sound into account. “Our next goal is to disentangle the role of sound relative to the perception of “heaviness,” and to determine if jays use the same sensory cues for acorns — their natural food,” conclude Dr. Lee and Dr Jablonski.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/05/150522174719.htm  Original web page at Science Daily

Shifting to renewable energy sources has been widely touted as one of the best ways to fight climate change, but even renewable energy can have a downside, as in the case of wind turbines’ effects on bird populations. In a new paper, a group of researchers demonstrate the impact that one wind energy development in Kansas has had on Greater Prairie-Chickens (Tympanuchus cupido) breeding in the area. Greater Prairie-Chickens are more likely to abandon mating sites near wind turbines, according to a new study in The Condor.

Shifting to renewable energy sources has been widely touted as one of the best ways to fight climate change, but even renewable energy can have a downside, as in the case of wind turbines’ effects on bird populations. In a new paper in The Condor: Ornithological Applications, a group of researchers demonstrate the impact that one wind energy development in Kansas has had on Greater Prairie-Chickens (Tympanuchus cupido) breeding in the area. Virginia Winder of Benedictine College, Andrew Gregory of Bowling Green State University, Lance McNew of Montana State University, and Brett Sandercock of Kansas State University monitored prairie-chicken leks, or mating sites, before and after turbine construction and found that leks within eight kilometers of turbines were more likely to be abandoned.

Leks are sites at which male prairie-chickens gather each spring to perform mating displays and attract females. The researchers visited 23 leks during the five-year study to observe how many male birds were present and to record the body mass of trapped males. After wind turbine construction, they found an increased rate of lek abandonment at sites within eight kilometers of the turbines as well as a slight decrease in male body mass. Lek abandonment was also more likely at sites where there were seven or fewer males and at sites located in agricultural fields instead of natural grasslands.

This paper is the latest in a series of studies on the effects of wind energy development on prairie-chickens. “To me, what is most interesting about our results is that we are now able to start putting different pieces of our larger project together to better understand the response of Greater Prairie-Chickens to wind energy development at our field site,” says study co-author Virginia Winder. “We have found that both male and female prairie-chickens have negative behavioral responses to wind energy development. The data we collected to monitor this response have also allowed us new insights into the ecology of this species. For example, lek persistence at our study site depended not only on distance to turbine, but also male numbers and habitat.”

The findings of this study reinforce the U.S. Fish and Wildlife Service recommendation that no new wind energy development should be done within an eight-kilometer buffer around active lek sites. “It is critical to have rigorous evaluations of direct and indirect effects of wind energy facilities on species such as prairie-chickens,” according to grassland wildlife management expert Larkin Powell, who was not involved with the research. “The potential for trade-offs between renewable energy and wildlife populations on the landscape is one of the key questions of our day.”

http://www.sciencedaily.com/ Science Daily

http://www.sciencedaily.com/releases/2015/05/150506164232.htm  Original we page at Science Daily

How to protect your chicks from predators? Build a dome over them! There is tremendous diversity among the nests of birds, in nest location, structure, materials, and more, but we know very little about the forces that shaped the evolution of this incredible variety. In a new paper published in The Auk: Ornithological Advances, Zachary Hall, Sally Street, Sam Auty, and Susan Healy of the University of St. Andrews in Scotland test the hypothesis that domed-shaped nests arose as a result of some species transitioning to nesting on the ground, where the risk from predators is greater.

Hall was completing his Ph.D. work on the neurobiology of nest-building behavior when he noticed that very little work had been done on trying to understand why different bird species build such drastically different nest structures. “I thought this was strange,” he explains, “because the shape of a nest seems to be the most striking and diverse feature across bird species.” The hypothesis that dome-shaped nests resulted from the increased predation risk when competition for nest sites led some birds to begin nesting on the ground was first proposed almost twenty years ago, but techniques at the time did not provide a way to test it. Applying statistical techniques he had previously used in his neurobiology study, Hall and his colleagues collected previously published descriptions of the nests of 155 species of babbler and mapped nest height and structure to the birds’ family tree.

Their analysis confirmed that babblers’ ancestors likely built above-ground, cup-shaped nests, and that the addition of a dome to cover the nest corresponded with switching to nesting at ground level. “This new study by Hall, Street, Auty, and Healy looks at the evolution of two key aspects of animals as architects: how they shape their homes and where they put them. It shows very nicely how we can take advantage of recent progress in avian phylogenetics to test ideas about the evolutionary history behind the modern-day co-occurrence of particular pairs of traits,” according to Don Dearborn, an expert in the evolution of reproductive strategies in birds. “I am very happy how well nest structure integrated into our analyses, but this study is only the tip of the iceberg, and we hope future work can use a similar approach to identify other factors that may have influenced the evolution of nest structure,” adds Hall.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/05/150506164238.htm  Original web page at Science Daily

The parakeets that have invaded Europe and North America over the last forty to fifty years, creating massive nests in many urban areas, seem to have originated from the same small geographical area in South America. In addition, the invasive populations are genetically identical and are recognized by a relatively rare dominant haplotype in the source population, an international team of researchers has concluded. The parakeets that have invaded Europe and North America over the last forty to fifty years, creating massive nests in many urban areas, seem to have originated from the same small geographical area in South America. In addition, the invasive populations are genetically identical and are recognised by a relatively rare dominant haplotype in the source population. This has been the conclusion of an international study in which Spanish scientists have participated.

The monk parakeet (Myiopsitta monachus), also known as the quaker parrot, is considered one of the most invasive bird species on the whole planet. Hundreds of thousands of them have been imported as pets over recent decades and their feral populations started to become an invasive species in the U.S.. in the 1960s and in Europe in the 1980s. However, these two independent populations seem to have originated from the same area of natural habitat, probably located between the south of Brazil (Río Grande do Sul), Argentina (Entre Ríos) and Uruguay, according to a study published in the journal Molecular Ecology in which the Doñana Biological Station (EBD-CSIC), the Pablo de Olavide University in Seville (UPO) and the Natural Science Museum in Barcelona have also participated. “For the study we used genetic information obtained from mitochondrial DNA and microsatellites to evaluate the genetic variability of the native area, South America, as well as three invaded areas located on three continents (North America, Europe and Africa) for the invasive species the monk parakeet Myiopsitta monachus,” Martina Carrete, co-author of the study and researcher for EDB and the UPO, explains to SINC.

Exotic invasive species are a fundamental component of global change and one of the main causes of native species dying out. It is for this reason that the variables determining the success of the establishment of such species have been studied from multiple perspectives. “Among other things, the existence of genetic variability is thought to be important, although there is no clear consensus on how this variability in the source populations and demographic processes affect the success of invasive species establishing themselves,” Carrete adds. The parakeets have been sold across the world as pets for years and have established invasive populations in many areas. “In particular, we evaluate whether the genetic diversity of invaded areas is a result of the genetic variability existing in the source populations (from which individuals have been imported) or demographic processes occurring during the introduction of these individuals,” comments the expert. Genetic diversity is lower in the invasive species

The study, which unravels the history behind the global parakeet invasion, also discovered that the North-American and European parakeets have less genetic diversity in their invasive populations than in their native populations. “Genetic data indicates that the source of the individuals which have stocked the invasive populations has a more restricted geographic origin, with little evidence for there having been a significant mix between the populations dwelling in the native geographical area,” stresses Carrete. This pattern matches the historical data on the export of individuals for their use as pets, which suggest that the majority of the individuals sold originate from the same area. “However, the invasive populations are more similar amongst themselves than would be expected just from this export data,” states the researcher.

In effect, the genetic variability observed in the invasive species is low, and suggests the existence of a demographic contraction and a restricted area of origin, but does not support the hypothesis that this invasion has been helped along by the mix and genetic recombination between individuals from multiple source populations. On the contrary, the scientists suggest that the reduced genetic variability observed in these invasive populations would not have negatively affected the success of their colonisation.

The reduced variability and great similarity presented in the invasive species studied suggest that convergent selection processes have also played a part in favouring the maintenance of certain haplotypes. “The presence of certain genetic characteristics would be important in explaining the success of the invasive species. Selection processes may also exist which determine this convergence in the genetic pattern of the invasive populations,” concludes the scientist. These selection processes during the invasion have not been considered before in these types of studies and could be important in explaining the success of certain invasive species.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/05/150511091429.htm  Original web page at Science Daily

With puzzling variability, vast numbers of birds from Canada’s boreal forests migrate hundreds or thousands of miles south from their usual winter range. These so-called irruptions were first noticed by birdwatchers decades ago, but the driving factors have never been fully explained. Now scientists have pinpointed the climate pattern that likely sets the stage for irruptions — a discovery that could make it possible to predict the events more than a year in advance.

The researchers found that persistent shifts in rainfall and temperature drive boom-and-bust cycles in forest seed production, which in turn drive the mass migrations of pine siskins, the most widespread and visible of the irruptive migrants. “It’s a chain reaction from climate to seeds to birds,” says atmospheric scientist Court Strong, an assistant professor at the University of Utah and lead author of the study. Many seed-eating boreal species are subject to irruptions, including Bohemian and cedar waxwings, boreal chickadees, red and white-winged crossbills, purple finches, pine and evening grosbeaks, red-breasted nuthatches, and common and hoary redpolls. The authors focused on the pine siskin, a species featured prominently in earlier work on irruptive migrations.

Previous studies have found evidence that irruptions are triggered by food shortages caused by the large-scale collapse of seed production in northern pine, spruce and fir forests. “We’ve known for a long time that weather was probably important, but prior analyses by ecologists have been unable to identify exactly what role weather was playing in this phenomenon,” says ecologist Walt Koenig, a senior scientist at the Cornell Lab of Ornithology and co-author of the new study incorporating climate science. “It’s a good example of the value of interdisciplinary work,” Koenig says. To resolve the question, the scientists turned to a remarkable trove of data gathered by backyard birders as part of Project FeederWatch, a citizen science initiative run by the Cornell Lab of Ornithology. FeederWatcher volunteers systematically record bird sightings from November through early April and they gave the scientists more than two million observations of pine siskins since 1989. The crowd-sourced data makes it possible to track the movement of bird populations at a continent-wide scale.

“Avid birders across the U.S. and Canada have contributed sustained observations of birds at the same broad geographic scale in which weather and climate have also been observed and understood,” says co-author Julio Betancourt, a senior scientist with the U.S. Geological Survey in Reston, Virginia. Pine siskins breed during summer in Canadian boreal forests, where they rely heavily on tree seeds for food. When seeds are abundant, pine siskins in eastern North America largely stay put in the northern coniferous forests of Canada through the winter. But when seed production is poor, pine siskins and other boreal birds move elsewhere to find overwintering habitat with adequate food. During these irruptive years, the eastern populations of pine siskins forage as far south as the Appalachian Mountains. Western populations show less variability in irruptive movements.

Amateur birdwatchers have recorded dramatic shifts in siskin migrations over the years. The winter ending in 1990, for example, featured a massive “superflight” south of the boreal forest, while during the winter ending in 2004 there was a near absence of boreal pine siskins in the U.S. The winter ending in 2009 saw another big irruption south of the boreal forest, followed by greatly reduced counts the following winter. In the new study, researchers combined FeederWatch observations with climate data in a statistical analysis. This allowed them to link bird population movements with established patterns of climate variability across North America. As expected, they found that extremely cold winters tend to drive birds south during the irruption year.

More surprisingly, the researchers found a teeter-tottering pattern between the north and south that influences bird migrations two to three years later. When the prevailing weather is wet and cold and unfavorable to seed production in one region, it tends to be warmer and drier and favorable to seed production in the other region. This climate “dipole” tends to push and pull bird migrations across the continent. The heaviness of seed production in a given year depends on how favorable the climate was during the two or three previous years required to set and ripen seeds. That means that, in principle, it might be possible to predict irruptions up to two years in advance. The finding also raises a question about the impact of global climate change: could the perturbation by massive carbon dioxide emissions disrupt the coupling between north and south such that unfavorable conditions unfold simultaneously, leaving birds with poor seed supplies everywhere in some years?

The answer is unknown. “The boreal forest is the world’s largest terrestrial biome and is home to more than half of North America’s bird species,” says co-author Benjamin Zuckerberg, an assistant professor of wildlife ecology at the University of Wisconsin-Madison. “It is likely that these irruptions, driven by climate, are a critical indicator of how climate change will affect northern forests and their dependent species.”

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/05/150511162906.htm  Original web page at Science Daily

New research from a Wake Forest University biologist who studies animal behavior suggests that evolution is hard at work when it comes to the acrobatic courtship dances of a tropical bird species. Assistant professor of biology Matthew Fuxjager studies the physiological basis of bird behavior, with a particular emphasis on how hormones control complex social behavior. For his latest study, published April 13 in the journal Functional Ecology, he investigated how the ability to detect testosterone in the body regulates the acrobatic courtship and competitive behavior, or bird brawn, of male golden-collared manakins. “Our results provide the first evidence that androgenic sensitivity in select parts of the neuro-motor system is an evolved mechanism to facilitate performance abilities and acrobatics in physically elaborate socio-sexual displays,” Fuxjager said.

There are about 60 different species of manakins, most of which perform, to some degree, a physically complex display behavior to both court females and to compete with other males, he said. The researchers hypothesized that evolution acts to help shape the mating display behavior by controlling androgen sensitivity in the avian wing muscles. They measured androgen receptor (AR) levels in these tissues in multiple species of manakins that varied in terms of the physical complexity of their display to see whether this measure of androgen sensitivity corresponds to species differences in physical complexity of the display. What they found is that those birds with more complex displays had muscles more sensitive to testosterone. “This research has some interesting implications for how evolution exploits testosterone’s ability to influence muscle and natural forms of athleticism,” Fuxjager said. “Our current data support the hypothesis that sexual selection shapes levels of androgen receptors expressed in the forelimb skeletal muscles to help drive the evolution of adaptive motor abilities.” Fuxjager said elaborate physical displays are found in most species, but little is known about how physically complex movements are linked to sexual reproductive behavior or fighting. He plans to continue to study how testosterone sensitivity and other aspects of the genetics of muscle physiology have evolved across species to develop these behaviors.

http://www.sciencedaily.com/  Science Daily

http://www.sciencedaily.com/releases/2015/04/150422084051.htm  Original web page at Science Daily

A new study shows that many bird species, including several of high conservation concern, aren’t getting the habitat they need due to a focus on promoting California Spotted Owl habitat in the northern Sierra Nevada. The study, published in the science journal, PLoS ONE, tracked different bird species’ use of areas inside and outside Spotted Owl reserves for two years in Plumas and Lassen National Forests. The results show 17 species avoided the reserves, including species of conservation concern like Yellow Warblers and Olive-sided Flycatchers, compared with only seven species preferring the habitat inside the reserves. Federal land managers have set aside reserves, or core areas, covering 1000 acres each of relatively mature and dense forest around historical or existing Spotted Owl nest locations. Unlike their cousin, the Northern Spotted Owl, California Spotted Owls currently are not federally listed as endangered.

“There is an absolutely clear need to continue to protect old growth forests,” said Ryan Burnett, Sierra Nevada Group Director for Point Blue Conservation Science and the study’s lead author. “However, we’re at a stage now where it’s time to re-evaluate our sometimes singular focus on old-growth forest management, and ensure we are balancing it with providing diverse forest habitats for the full range of species that rely on the Sierra ecosystem.” In the northern Sierra area of the study over 50 percent of the National Forest land base is designated to promote and protect mature, closed-canopy forest that supports less undergrowth, such as shrubs and grasses. Many bird species–and other wildlife–seek out undergrowth and the habitat provided in forest openings for food, shelter and nesting.

As part of the study, Burnett and colleagues monitored the bird community at 1,164 locations inside and outside Spotted Owl reserves. They found that they could conclusively determine the habitat preference for 24 bird species detected. Of those 24 species, 17 preferred habitat outside the reserves and only seven preferred habitat inside the reserves. Another 30 species were detected but it was unclear if those birds showed a preference or not. “Our current forest management may be focusing too much on a handful of mature, dense forest-associated species at the expense of others, including several of high conservation concern,” Burnett said. “The Sierra ecosystem evolved with disturbance, such as wildfire. It’s important we manage the areas outside of the old growth reserves for the wide range of habitat types and conditions that support a substantial portion of the ecosystem’s biological diversity, including early seral forest habitat.”

According to Burnett, a combination of forest management actions could promote habitat for many other species outside the reserves. An increased use of managed fire coupled with selective logging to thin overly dense forest stands can benefit many of the species that avoid mature, dense forest habitat and promote an ecosystem more aligned with current and future climate conditions.

http://www.nature.com/news/index.html  Nature

http://www.sciencedaily.com/releases/2015/04/150428142100.htm

Original web page at Nature

The ancient sport of falconry is embracing high-tech hunting, with falconers using robots to train their birds. The move could help conservation efforts. Mascuch, an experienced falconer in Parma, Idaho, was nursing the bird back to health after she had suffered a broken wing. The quadcopter, which Mascuch had fitted with blade guards, was placed on the ground next to his falcon. She eyed it warily. As the motors started up, Mascuch distracted her from the noise with a snack. Soon the bird was up in the air, chasing the drone – and the half a quail dangling from it. Her owner is now a drone convert. “It’s easy to use, quick and very versatile,” says Mascuch. “If you have a bird that’s difficult to train, these tools make it easy.”

Drones have taken the ancient sport of falconry by storm over the past few years. Falconers train their birds to reach high altitudes, so that they can see across larger areas and are more likely to find prey. Traditionally, they have done this by rewarding the falcon whenever they happen to fly high. Some trainers tempt the birds upwards with bait attached to a kite or balloon. But drones offer more control over this process – they can make the bait fly where the trainer wants or hover, even in a stiff breeze.

“To the average person, it would seem like this great leap forward, but it’s really an evolution of what falconers have done for a long time,” says Mike Dupuy, a falconer in Pennsylvania who plans to incorporate drones into his training. “It’s a beautiful thing, it’s a new thing and I think we’re going to get a lot more of it.”

http://www.newscientist.com/  New Scientist

http://www.newscientist.com/article/mg22530132.600-falcons-learn-to-hunt-by-chasing-  drones.html#.VQ_D8lI5Bkg Original web page at New Scientist

Researchers have established that birds can sense the earth’s magnetic field and use it to orient themselves. How this internal compass works, though, remains poorly understood. Physicists at the University of Oxford are exploring one possible explanation: a magnetically sensitive protein called cryptochrome that mediates circadian rhythms in plants and animals. Blue or green light triggers electrons in the protein to produce pairs of radicals whose electron spins respond to magnetic fields. “As we vary the strength of the magnetic field, we can alter the progress of these photochemical reactions inside the protein,” said lead researcher Peter Hore, who will present his work during a talk at the American Physical Society’s March Meeting on Wednesday, March 4 in San Antonio, Texas. Behavioral experiments have shown that even subtle disruptions to the magnetic field can impact birds’ ability to navigate.

In a study led by Henrik Mouritsen, in collaboration with Hore, robins were placed in wooden huts on campus at the University of Oldenburg in Germany. Without supplementary visual cues like the sun’s position in the sky, the birds struggled to navigate. They only regained their ability to orient themselves when the huts were covered in aluminum sheeting and electrically grounded, blocking external oscillating electromagnetic noise but not the earth’s static magnetic field. The researchers concluded that even low-level electromagnetic noise in the frequency range blocked by the aluminum screens — probably coming from AM radio signals and electronic equipment running in buildings –somehow interfered with the urban robins’ magnetic orientation ability. Hore hopes that the behavioral findings in the field can inform his molecular-level work in the laboratory. “We would like to know how such extraordinarily weak radiofrequency fields could disrupt the function of an entire sensory system in a higher vertebrate.

Our feeling is that this is likely to provide key insights into the mechanism either of the magnetic compass sense or of some important process that interferes with the birds’ orientation behavior,” said Hore. One explanation is that the electromagnetic noise has quantum-level effects on cryptochrome’s performance. This would suggest that the radical pairs in cryptochrome preserve their quantum coherence for much longer than previously believed possible. Such a finding could have broader implications for physicists hoping to extend coherence for more efficient quantum computing. “Physicists are excited by the idea that quantum coherence could not just occur in a living cell, but could also have been optimized by evolution. There’s a possibility that lessons could be learned about how to preserve coherence for long periods of time,” said Hore.

http://www.sciencedaily.com/ Science Daily

http://www.sciencedaily.com/releases/2015/02/150227131003.htm Original web page at Science Daily