Tag Archives: research

Good grief! Losing a friend brings wild birds closer together

(Physorg, Oxford University 17 May 2017;Photo: Molly Harwood)

New Oxford University research has revealed that instead of grieving, wild birds appear to adjust to the loss of a flockmate by increasing both the number and intensity of their relationships with other birds.

Human impacts around the globe are causing increasing numbers of wild animal populations to decline. The effects of losing a mate, friend or group member on remaining animals’ social behaviour is currently little understood. The research newly published in the journal Proceedings of the Royal Society B, sought to improve our understanding of how wild animals cope with loss.

Scientists from Oxford University’s Department of Zoology tracked the social interactions between more than 500 wild great tits over winter, whilst temporarily removing birds from flocks at random. By doing so, the team were able to assess how wild birds respond to losing their flockmates, providing new insights into social behaviour which may also have valuable implications for conservation programs.

Lead author, Postdoctoral Research Fellow Dr Josh Firth said: ‘We found that individual birds adapt to losing a flockmate by increasing not only the number and tightness of their social relationships to others, but also their overall connectedness within the social network of remaining individuals.’

Previous computational research has suggested that losing individuals may cause animal social systems to break down but the new findings suggest a brighter picture. If animals have the ability to adapt to the disruption caused by losing members of their group, important processes like information transmission may be maintained better than expected. In the same sense, strategies that focus on culling individual animals to prevent disease spread may be futile if the remaining animals respond by making new social links.

This research represents the first experimental test of how wild animal social networks respond to loss, and the findings share clear parallels with a recent study that looked at how losing a friend impacts human social networks. The human-based research used data from Facebook to show that following the death of a user friends of the deceased appear to become closer and increase their interactions over Facebook with each other.Dr Firth said: ‘Great tits are very sociable birds, and their relationships shape almost every aspect of their lives. A real benefit of studying these birds is that we can run experiments to test the principles of social behaviour. Interestingly, in this case the results appear surprisingly similar to what has been suggested for humans.’

‘Now we understand how birds adjust their social behaviour upon losing randomly chosen flockmates, we want to experimentally test the consequences of removing the key players and the most sociable individuals for conservation-related processes such as information and disease spread.’

Conservation partnership launches “floating islands” in bid to save rare duck

commonscoters.jpg(RSPB 15 May; Photo Graham Catley)

An unprecedented partnership of organisations from industry and the conservation sector has come together in a bid to save the common scoter as a breeding bird in the Highlands of Scotland. The birds, which breed on the edges of a small number of lochs, will be helped by the creation of artificial floating islands made from redundant materials from fish farms. It is hoped that the scoters will choose to nest on the islands and this will make the nests safer from the unwelcome attention of predators and the risk of being flooded.

RSPB Scotland’s Dr Alison MacLennan said, “Within the last forty years the population of the now inappropriately named Common Scoter has fallen from several hundred pairs, with a wide distribution over the north and west of Scotland, to around fifty pairs found in a few isolated lochs. We are in real danger of losing this lovely bird as a breeding species in Scotland and I am delighted that this partnership has come together to help provide them with a future.”

Research conducted by a partnership of organisations including the Wildfowl and Wetlands Trust (WWT), Scottish and Southern Energy (SSE), Forestry Commission Scotland (FCS), Scottish Natural Heritage (SNH), Blue Energy, the Ness & Beauly Fisheries Trust and RSPB , has pointed to a number of causes for this decline, many of which are linked to changing uses in the landscape.
In addition, mammalian predators have been identified as having a significant detrimental effect on the survival of common scoter nesting attempts and their success in hatching ducklings. In an attempt to address this problem in some of the Inverness-shire lochs, the partnership group joined forces with Fusion Marine and Marine Harvest to produce floating islands that will provide the ducks with safer nest locations with a reduced risk of predation.

Two of these islands have now been sited in common scoter breeding lochs in Inverness-shire as a trial to see if their use can boost the ducks’ success in rearing their young.

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Picky fruit-eating birds are more flexible

(Senckenberg Research Institute and Natural History Museum 11 May 2017; Photo Matthias Dehling )

Researchers from Senckenberg and the German Centre for Integrative Biodiversity Research have found that South American birds that are seasonally specialized on particular fruit types are the most flexible in switching to different fruit types in other seasons. This flexibility in their diet is good news in view of the predicted loss of plant species under global change. The study is published in the Journal of Animal Ecology.

The Plumbeous pigeon is a picky eater. Whereas its relatives on European streets and squares feed on whatever they encounter, its South American relative almost exclusively feeds on certain fruits. Together with other birds such as toucans or the turkey-like guans it belongs to a bunch of large fruit-eating birds that are specialized on particular types of fruits. One might think that being peculiar goes hand-in-hand with being inflexible in food choice — however, it does not.

“We compared neotropic fruit-eating birds that are specialized on a small range of fruit resources in a particular season with birds that eat a large ranage of fruits. The specialists are those which are most flexible in adapting their foraging choices across seasons,” explains Irene Bender, Senckenberg Biodiversity and Climate Research Centre and German Centre for Integrative Biodiversity Research (iDiv), lead author of a new study on this topic. She adds “The flexible avian fruit eaters prefer to feed on large fruits. However, their favourite resources are not constantly available throughout the year which forces them to switch.”

The researchers’ surprising observations shed light on the question how species might respond to resource fluctuations that are not naturally determined. “This flexibility of consumer species may be an important, but so far widely neglected mechanism that could stabilize consumer-resource relationships, for instance in response to human disturbance and environmental change. Being flexible might mean that specialized foragers are able to adapt to future changes in resource availability.” says Dr. Matthias Schleuning, Senckenberg Biodiversity and Climate Research Centre.

The study was based on observational records by a team around Irene Bender and Matthias Dehling of the fruit choices of birds in the Manú Biosphere Reserve on the western slopes of the Andes in Peru. The team also measured traits of the plants which provided the fruits, such as plant height and fruit size. The flexibility of bird species was defined as their ability to switch seasonally among plant species with different traits; their specialization was measured by comparing their fruit choices to those of other bird species in the community.

Birds change song to be heard above traffic noise

(Julia John 2 may 2017; Photo Kelly Colgan Azar )

Vehicles are a major source of noise pollution for urban wildlife. That’s particularly a problem for birds that have to compete with the roar of engines to communicate. Recent research from Washington, D.C., suggests that some birds —those with innate rather than learned songs —modify their song structure to be heard over the din of traffic.

In noisier conditions, these birdsongs are shorter and have a smaller range of frequency, said Katherine Gentry, lead author on the paper published in Bioacoustics. The birds raise their minimum frequencies, reducing their song’s overlaps with low frequency traffic noise.

“That makes it easier for the receiver to detect the signal against the background noise,” said Gentry, a research assistant at George Mason University.

Gentry wanted to see if suboscines, a family of birds whose song is innate rather than learned, could adjust their signal to communicate over traffic noise. Suboscine species include the vermilion flycatcher (Pyrocephalus rubinus), chocolate-vented tyrant (Neoxolmis rufiventris), white monjita (Xolmis irupero) and eastern wood pewee (Contopus virens). Although many studies have examined birds’ response to noise pollution from vehicles, this was the first to look at how suboscines in particular change their song in the absence of traffic during temporary road closures.

Gentry recorded the song of the eastern wood pewee in Rock Creek Park, a large urban park in Washington, D.C. She then compared recordings from times when traffic noise was high and times it was low, including weekends, when roads were closed to vehicles to allow for cycling and joggers. “This study showed that suboscines can adjust their song as traffic noise fluctuates,” Gentry said. That’s good for the birds in that it allows them to improve their chances of successful communication, she said.

“Even though they’re improving the likelihood of signal reception, they’re potentially sacrificing the sexiness of their song,” Gentry said. “With that minimum frequency raised, they’re not singing that naturally selected song structure.”

Songs with a higher minimum frequency that have a narrower range of frequencies could negatively influence the birds’ ability to defend territories, find mates and reproduce if females and rival males respond more strongly to signals with wider bandwidths.

But Gentry also found that when the roads were closed and it was quieter, the birds sang more naturally. Even though a permanent reduction in traffic noise is most ideal, she said, road closures could benefit birds like these that alter their songs in response to higher traffic noise levels.

“Noise is an issue for animals,” Gentry said. “Even if they cope through signal adjustment, it could be affecting them in the long run. It’s important we make every effort to reduce it. It would be a broad benefit for the community.”

Under-Studied Boreal Habitat Key for North America’s Ducks

CONDOR-16-179 M Carriere

(AOS; Photo: M. Carriere; 19 April 2017)

Knowing where migrating birds came from and where they’re headed is essential for their conservation and management. For ducks, most of this information comes from long-term bird-banding programs, but this type of research has limits—despite all the birds harvested by hunters, only a small percentage of banded birds are ever recovered. A new study from The Condor: Ornithological Applications takes on the challenge of gaining information from unbanded birds by using stable isotope ratios, which reflect where birds were living while growing their feathers. These results reveal that the northern reaches of Canada may have underappreciated importance for North America’s waterfowl.

Canada’s Saskatchewan River Delta is North America’s largest inland delta and is a key stopover site for migrating ducks. To learn more about the origins of ducks using delta habitat, Christian Asante of the University of Saskatchewan, Keith Hobson of the University of Western Ontario, and their colleagues analyzed the isotopes in feather samples from 236 ducks from five species, all harvested by hunters in the region during migration in 2013 and 2014. Hydrogen and sulfur isotope ratios give scientists different information—hydrogen isotope ratios vary predictably with latitude, while sulfur isotope ratios reflect the type of food a bird eats and underlying geology—but together they indicated that as many as half the ducks using the delta during migration originated in the vast and nearly inaccessible areas of boreal forest and wetlands to the north.

The research required close collaboration with the area’s hunters. “Working on this project was a great experience,” says local community member Michela Carriere, who was hired to do the field work for the study. “I spent a few weeks collecting samples from the ducks and getting to know the hunters and the guides. Twice a day a load of ducks would come in and I would collect samples and label and package them, plucking feathers and extracting tissues. The hardest part was the labeling, which has to be done meticulously. I would spend hours each day collecting and organizing the samples.”

The results show that the boreal habitat’s contribution to North America’s waterfowl populations, though poorly documented, may be crucial. This region faces increasing threats from climate change and other factors, and isotopic monitoring offers a new means of tracking the effects on birds. “Our study is important for two reasons,” says Hobson. “First, it demonstrates clearly that the delta is a major fall refueling station for birds breeding in the north. Second, it shows once again how origins and regions of productivity can be determined using the simple isotope approach with feathers from hunter-killed birds. This major potential tool in waterfowl management has been largely overlooked in North America for too long.”

‘Happy wife, happy life’ meaningful for birds, too

‘Happy wife, happy life’ meaningful for birds, too (Victoria University; 19 April 2017)

Research from Victoria University of Wellington has shown for the first time that wild male birds read their partner’s behaviour to appropriately cater to her food desires.

Dr Rachael Shaw, a postdoctoral research fellow in Victoria’s School of Biological Sciences, conducted a study on a group of North Island robins based at Zealandia.

The research investigated whether male robins could give their mate the type of food that she was most likely to want during reproduction.

“Robins are a monogamous, food-sharing species, so were ideal for this experiment. The experimental procedure has only previously been used in the laboratory on Eurasian jays,” she says.

“We found male robins appropriately catered to their mates’ desire, even when the female’s behaviour was the only cue available to guide their choices.

“This suggests that females can signal their current desires to their mates, enabling males to respond to that.”

Dr Shaw says the finding raises the possibility that other species might be capable of doing the same.

“In many species food sharing by the male is vital to help the female offset the energetic costs of reproduction, such as egg laying and incubation. The male’s ability to give his mate what she wants could in fact be an important factor in determining the success of a pair, as well as influencing whether they stay together. These are really exciting avenues for future research.”

The experiment first involved establishing female robins’ eating habits. “I fed the females either meal worms or wax worms, and then gave them the choice between these two types of insect larvae. I found that after the females had eaten one type of insect, they would prefer to eat the other type when given the choice. This means that the female’s desire for a particular food is affected by what she has previously eaten.”

Based on this, Dr Shaw then tested if the male would also be able to choose the type of insect his mate was most likely to want (the one she had not just eaten).

“Regardless of whether or not he had seen what his mate ate first, the male still made the appropriate choices. This suggests that the female is likely to be displaying her current desire in her behaviour, and that the male is using these cues to identify the food that she wants.”

The research, co-authored by Victoria’s Associate Professor Kevin Burns and Professor Nicola Clayton from the University of Cambridge in the United Kingdom, was recently published in the journal Scientific Reports.

The field work and data collection was carried out by Dr Shaw with help from Victoria student Regan MacKinlay. Dr Shaw’s research is supported by a Rutherford Foundation postdoctoral fellowship and a Marsden Fast Start grant from the Royal Society of New Zealand.

Bird brains not so stupid: pigeons show human-like ability to build knowledge through generations

Homing pigeons return from Pennsylvania to their home in New York City

(; Photo: Jim Cooper; 18 April)

Having, literally, bird brains, pigeons are not generally considered to be the most intelligent of creatures.

But new research reveals that in a crucial respect they are more like humans than any other.

Scientists at Oxford University found that homing pigeons are the only known species in the world other than humans able to build and pass on wisdom across the generations.

While many animals teach basic skills to their young, such as learning to hunt, until now none had shown it was possible to improve the collective ability of their species in the way mankind becomes ever more advanced.

But the scientists found that in the case of homing pigeons, families of the bird were able to improve their efficiency navigating across large distances over time.

They sent pairs of the homing pigeons off on a specific route, and then continuously replaced one experienced bird from a couple with an inexperienced one who had never flown the course before.

The experiment was designed to establish whether individual birds could pass their experience of the route down to the next pairing, and to see if the collective intelligence of the group improved so that their efficiency over the route improved.

Published in the journal Nature Communications, the study showed that the group’s homing performance got consistently better, and that each new pair of pigeons flew a more streamlined route over the course.

The homing pigeon navigates by means of magnetoreception, which allows it to detect a magnetic field to perceive direction, altitude and location.

In the study, later generation groups were found to outperform those who flew solo or as part of pairing which never changed.

Dr Takao Sasaki, who co-led the research, said: “At one stage scientists thought that only humans had the cognitive capacity to accumulate knowledge as a society.

“Our study shows that pigeons share these abilities with humans, at least to the extent that they are capable of improving on a behavioural solution progressively over time.”

The Oxford team pointed out, however…..

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