Mystery of birds’ movements at sea solved

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RSPB 7 July 2017; Photo Chris Gomersall)

  • New research reveals where British and Irish seabirds go when they’re not on land.
  • The five year project GPS-tracked over 1,300 breeding seabirds and used computer models to predict where they go to find food.
  • Results reveal the majority of ‘hotspots’, where seabirds gather to feed, are concentrated in the coastal waters of Scotland, highlighting the need for robust conservation measures in this area.
  • The new maps will be used to protect threatened species by assessing potential impacts from offshore wind farms, pollution and other human activities on seabirds.  

New research has identified the most important areas for Britain and Ireland’s seabirds at sea, with the majority of ‘hotspots’ revealed in the coastal waters of Scotland.

Experts used GPS-tracking (1) and computer models on an unprecedented scale to map where breeding seabirds go when they leave land to feed, providing a unique insight into the lives of these enigmatic birds.

The study (2), headed by the RSPB in partnership with over a dozen scientists from leading research institutes (3), used five years of tracking data to estimate the areas used by four species: kittiwakes, shags, razorbills and guillemots.

This comes as the Scottish Government considers the creation of Special Protection Areas at sea to safeguard key seabird feeding areas, as well as planning future management of marine activities in Scottish waters outside of the EU and the Common Fisheries Policy.

During the project, lightweight GPS tags were fitted to over 1,300 adult birds from 29 different colonies. The tracking data was then used to create a computer model for each species, so that all of the important areas at sea could be predicted.

The results (see study maps attached) show the extent to which birds travel to find food. The majority of seabird ‘hotspots’, where different species gather to feed, are concentrated in the coastal waters of Scotland, highlighting the need for robust conservation measures to protect these areas. Overall, the four species use at least 1.5 million square km of sea around Britain and Ireland – an area three times the size of Spain.

This is a major step forward in our understanding of seabirds and is a powerful tool to help protect birds from potentially harmful activities at sea, including helping to make better decisions about where those activities can be undertaken to limit their impacts on seabirds.

Understanding more about our seabirds is vital because they are one of the most endangered groups of birds in the world. Over the last 30 years, kittiwake and shag numbers have declined by 72% and 68% respectively in Scotland. This is partly due to the impacts of climate change and fishing, and a new OSPAR report (4) underlines this trend, highlighting widespread seabird breeding failures in the North and Celtic Seas. Scotland is also home to internationally important populations of breeding seabirds so we have a global responsibility to safeguard them.

Dr Mark Bolton, RSPB Principle Conservation Scientist, said: “Our rich and diverse marine environment makes Britain and Ireland one of the greatest areas in the world for seabirds and this new research is further evidence of just how important our seas are for seabirds and their chicks during the breeding season. In order to strengthen this research and our predictions, there is an urgent need for a complete seabird census which will provide an accurate and up-to-date estimate of the size of our seabirds breeding colonies.”

Dr Ellie Owen, who led on the tracking work, said: “The sight and sound of hundreds of thousands of seabirds flocking to our shores is an amazing natural spectacle and something that we must help protect for future generations to enjoy. The methods used in this study could be applied to other seabird species, to show where they go at sea. This will be an invaluable tool in helping to protect seabirds, as it will greatly improve our ability to assess the likely impacts on breeding seabirds of offshore wind farms, oil spills and other potentially harmful activities in our increasingly industrialised seas.”

Dr Ewan Wakefield, lead author of the research, said: “Many seabirds are at the top of the marine food web. They feed on sandeels and other small fish but that prey is declining because of human pressures, including climate change. The result is that thousands of seabird chicks are dying each year because their parents can’t feed them. For the first time, this study provides us with a full map for each breeding colony of the feeding areas for some of our most important seabird species. That means we can now protect the places these birds catch the fish they need to feed their hungry chicks, securing the fate of future generations of these amazing creatures.”

Dance Moves Support Evidence for New Bird-of-Paradise Species

Western New Guinea form of the Superb Bird-of-Paradise

(Cornell LoO 29 June 2017; Photo Tim Laman)

Ithaca, NY—The Superb Bird-of-Paradise—the shape-shifting black bird of central New Guinea that woos its mate with an iridescent blue “smiley-face” dance—has an equally superb cousin in the isolated mountains of Indonesia’s Bird’s Head Peninsula in the island’s far west. Scientist Ed Scholes and photographer Tim Laman, with the Cornell Lab of Ornithology’s Birds-of-Paradise Project, have now visually documented the distinct differences between the western population in the Arfak Mountains and the more common form found elsewhere on the island. Both believe the western form should be considered a new species.

“The courtship dance is different. The vocalizations are different. Even the shape of the displaying male is different,” says Scholes. “For centuries, people thought the Superb Bird-of-Paradise in the mountains of the Bird’s Head region was a little different from the other populations throughout the rest of New Guinea, but no one had ever documented its display in the 200 plus years this bird has been known to occur there.”

“Even after many trips to the region, we’d never seen the Arfak birds do their courtship display,” says Birds-of-Paradise Project co-leader Tim Laman. “When we finally located a display site and saw a male open his cape for the first time, what we saw was a complete surprise!”

When expanded for courtship display, the western male’s raised cape creates a completely different appearance—crescent-shaped with pointed tips rather than the oval shape of the widespread form of the species. The way the western male dances for the female is also is distinctive, being smooth instead of bouncy.

           
The raised cape of the western male (left) is crescent shaped and unlike the oval shape of the widespread Superb Bird-of-Paradise (right) found throughout most of New Guinea. Left image by Tim Laman/Macaulay Library. Image on right is from video by Ed Scholes/Macaulay Library.

Scholes and Laman have been studying and filming birds-of-paradise behavior in the Arfak Mountains for the past 13 years. They first uncovered this population’s unique courtship behaviors in June 2016 and returned again this year to gather additional documentation for a forthcoming scientific paper.

A recently published independent genetic study confirms the visual and behavioral evidence collected by Scholes and Laman. A team of researchers from Sweden and Australia used DNA samples from museum specimens to examine the evolutionary relationships among Superb Bird-of-Paradise forms throughout New Guinea. Their research, published online in the Zoological Journal of the Linnean Society, found that the western form is more genetically distinct from the widespread form than previously thought. They, too, say the western population should be recognized as a full species called Lophorina neidda inopinata. 

“The timing of this DNA-based study is perfect,” said Ed Scholes, “because it is great to have our field observations supported by solid genetic evidence. We really appreciate this in-depth study of the evolutionary relationships among the different forms of Superb Bird-of-Paradise.”

The Cornell Lab’s Birds-of-Paradise Project (birdsofparadiseproject.org) is a research and education initiative to document, interpret, and protect the birds-of-paradise, their native environments, and the other biodiversity of the New Guinea region—one of the largest remaining tropical wildernesses on the planet.

Caterpillars key to urban blue tits’ low breeding

Caterpillars key to urban blue tits' low breeding
(Physorg; University of Glasgow 11 July 2017)

Many animal species suffer reduced reproductive success in urban habitats, despite wide-spread supplementation of breeding and feeding opportunities. In some years, the breeding success of city birds is devastatingly low.

Biologists have now shown conclusively that in urban blue tits, reduced breeding success is linked to poor nestling diet and in particular to scarcity of caterpillars, their preferred nestling food.

The research adds to growing concerns that urban environments can become ecological traps for urban-dwelling species. The increasingly rapid process of urbanisation has now placed more than 50 percent of the human population in cities. Birds and other species can be attracted to these habitats by human food and shelter, but these benefits can be offset by major ecological deficits, as now shown for blue tits.

Although blue tits are widespread songbirds that appear to do well, their breeding failure in cities can be severe. In 2015, blue tit parents fledged less than one chick per nest in parks in Glasgow, compared to more than five chicks per nest in the Loch Lomond National Park. Suburban sites showed intermediate breeding success. Researchers from the University of Glasgow and NERC’s LSMSF Facility (National Environment Research Council’s Life Sciences Mass Spectrometry Facility) at SUERC (Scottish Universities Environmental Research Centre) used a holistic study approach to reveal the reasons for this drastically low breeding success. Their research is published in the journal Scientific Reports.

The researchers counted caterpillars, other insects and spiders on the trees where blue tits forage. They found that caterpillars were greatly reduced in the city and did not show the typical seasonal peak on which chicks can thrive.

Filming the parents as they entered the nest boxes, the researchers discovered that the more caterpillars the parents delivered, the higher the fledging success of their young. However, although urban parents worked harder for each of their offspring, they provisioned far fewer caterpillars than forest birds. Instead, urban parents brought alternative foods, including peanut granules that the chicks were unable to digest. Dietary differences were also confirmed by analyses of stable isotopes in blood and egg samples of blue tits, which give clues to the food the birds had consumed.

Dr Barbara Helm, of the University of Glasgow’s Institute of Biodiversity, Animal Health and Comparative Medicine, said: “These losses of birds’ breeding success are avoidable if we take better care of urban biodiversity. Not all breeding seasons are as bad as 2015, but if conditions become tough, urban birds are hit much harder than birds in natural forests. Increasing caterpillar numbers will directly benefit birds in our cities”.

Dr Davide Dominoni, now at the Netherlands Institute of Ecology, added: “We should increase the birds’ provisioning of caterpillars from moths and butterflies, for example by prioritising native plant species that the caterpillars like,including oaks, and by reducing use of insecticides.”

The findings of this study make the strongest case to date that urban nestlings are not receiving a suitable diet. So far, these results have been based on single study sites in Scotland. More research is needed to confirm the reported patterns for other cities in the world. But the present study provides strong integrative evidence that diet is an important limiting factor for urban populations of this and potentially other species.

The team’s paper, titled ‘Integrated behavioural and stable isotope data reveal altered diet linked to low breeding success in urban-dwelling blue tits’, is published in Scientific Reports.

Boosting the breeding of New Zealand’s endangered birds

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(Physorg;Victoria University 11 July 2017)

New Victoria University research suggests hormones found in New Zealand’s native plants are helping endangered native birds to breed successfully.

The study, published in Reproduction, Fertility and Development and conducted by Victoria Ph.D. graduate Dr. Catherine Davis, looks at the potential link between parrot breeding and high levels of fruiting by native plants.

“A mast year is a year when plants produce masses of edible fruit or seeds,” explains co-supervisor Dr. Janet Pitman from Victoria’s School of Biological Sciences.

“Kākāpō breed only in mast years—that’s once every three or four years. So there’s something happening in those mast years that triggers their breeding.”

Kākāpō are critically endangered, with fewer than 160 known surviving birds.

Dr. Pitman says it’s been hypothesised that kākāpō require more of the hormone oestrogen than they can produce themselves to make a fertile egg.

“We know from other studies that oestrogens present in new grass may interfere with reproduction in animals, and we know kākāpō seek out fruit from rimu to eat during mast years.

“We believe kākāpō get extra oestrogen from their diet during mast years, and rimu and other native plants provide that extra oestrogen that is key to kākāpō reproduction.”

Dr. Pitman and her research team set out to shed light on this potential hormonal link.

“We tested various native plant species for oestrogenic content—and we found that indeed there is a high amount of oestrogen in some of New Zealand’s native plants,” she says.

“We also looked at the receptivity of parrots to oestrogen. We studied the genetic makeup of the receptor that is activated by oestrogens in the New Zealand kākāpō, kea, kākā, kākāriki, the Australian cockatiel, and compared them with those in the chicken.”

“We found that all of the parrot species have a unique sequence in this receptor gene that may make them more sensitive to oestrogen, compared to other bird species or humans.”

Dr. Pitman says this suggests the oestrogen produced in native trees may provide the link between mast years and successful breeding of parrots like kākāpō.

“With further research we’re hoping to identify the specific oestrogenic settings in native plants. This information may enable a synthetic model to be produced, so we could potentially use it increase the fertility of our native parrots.”

Lost in translation: To the untrained zebra finch ear, jazzy courtship songs fall flat

(Physorg 10 July 2017)

Zebra finches brought up without their fathers don’t react to the singing of potential suitors in the same way that female birds usually do, hinting that the environment in which the birds are raised can have a determining effect on their behaviour.

The finding, published in the Proceedings of the Royal Society B by McGill researchers, highlights how learning and experience, including developmental auditory experience, can shape how the brain perceives vocal signals.

The research adds to a growing body of evidence underscoring how specific experiences are necessary to shape the developing brain, and how the absence of specific inputs can have long-lasting effects on perception, neural processing, and behaviour.

Songbirds use courtship signals such as song to identify individuals and select a mate.

Zebra finch males each produce a single song, but they perform a “better” version when courting a female. There is accumulating evidence that females choose mates based on how well their potential suitor performs this “improved version”, providing information about his quality, condition and fitness.

Given the importance of being able to judge the subtle difference in the male zebra finches’ song, scientists imagined this skill to be innate within female zebra finches. To test that idea,

Sarah Woolley, professor at McGill’s Department of biology, and graduate student Nancy Chen decided to investigate how developmental exposure to adult male song might affect behavioural responses to song in female zebra finches.

“Because females use song in selecting a mate, we expected that females might have an inherent bias to recognize and prefer high-performance songs”, professor Woolley says.

Surprisingly, they found that a bird’s capacity to distinguish courting versus non-courting singing greatly depends on its upbringing.

Female zebra finches brought up with both of their parents reacted in the “normal” way and preferred the courtship songs of potential suitors. Females reared without their father’s songs didn’t consistently prefer high-performance courtship songs.

In other words, female zebra finches need to hear dad’s singing to help her distinguish which suitor sings best.

“In the wild, females would rarely be raised without a father/tutor,” professor Woolley notes. “That said, it could mean that the environment that birds are raised in will influence song preferences. We already know that male birds can shift their songs to make them easier to hear in noisy, urban environments. Our data could mean that the ability of females to detect those songs may be affected by what they hear when they are young.”

Touchscreen test reveals why some birds are quicker to explore than others

(Science Daily 10 July 2017)

Birds such as parrots and crows have been using touchscreen technology as part of an international research study examining whether the ways in which animals respond to new things influences how eager they are to explore.

The new research, involving scientists from across Europe, looks at how a number of factors affect the speed and frequency with which the birds investigate new objects that they have never seen before.

The study was carried out by researchers from the Messerli Research Institute (University of Veterinary Medicine Vienna) and the University of Vienna in Austria, the Max Planck Institute for Ornithology in Germany and University of Lincoln, UK.

It has generally been assumed that neophobic species (species that do not like new things) have a tendency to explore less than those that do (referred to as neophilic). For example, kea parrots in New Zealand have been known to destroy cars because they are so interested in new things.

The research results reveal that the neotic style of a bird (how neophobic or neophilic an animal is) has an impact on when they choose to explore new objects, but not on their level of exploration. Those who are more neophobic carry out the same amount of exploration, but simply make the approach much later. The results also show that juvenile animals explore more quickly than adults do.

Significantly, the scientists found that individual differences and characteristics seem to be much more important than species-level differences in determining how eager a bird is to explore. This suggests that neotic style is not, as is frequently assumed, a result of the challenges faced by an entire species, but instead appears to differ depending on the individual bird.

As part of the investigation, the parrots and crows were introduced to a touchscreen which revealed two different coloured shapes on a regular basis, and they were trained to understand that choosing one of the shapes (by pecking it) could result in a food reward. The researchers showed each bird 16 pairs of shapes, and throughout the task introduced a few novel stimuli that they had never seen before. The researchers measured how quickly they responded to the new shapes, and at which point in the test they chose to investigate them.

Dr Anna Wilkinson, a specialist in animal cognition from the School of Life Sciences at the University of Lincoln, explained: “Rather than its species, we found that individual differences have a significant impact upon how quickly a bird begins to explore. This is likely to be due to a combination of the bird’s age, its individual position in the social hierarchy, and its own previous experiences.”

The birds that featured in the study were from nine different species of parrots and corvids — also known as the crow family. They were selected to represent different ecological backgrounds so that factors such as the likelihood of pressure from predators could also be taken into account. For example, species originating from islands such as Goffin’s cockatoos and vasa parrots are less likely to face pressure from predators than those such as ravens, jackdaws and African grey parrots, which are much more widely distributed.

As part of the study, researchers worked with Eclectus parrots from the Lincolnshire Wildlife Park to assess their reactions.

The first author of the study, Dr Mark O’Hara from the Messerli Research Institute and the University of Vienna, said: “Our findings allow for a more accurate interpretation of behaviour and the processes which control responses to changes in the environment.”

The full paper, The temporal dependence of exploration on noetic style in birds, is published in Scientific Reports.

Decline in hummingbird population linked to insecticide

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(Terri Theodore 9 July 2017; Photo Darryl Dyck)

VANCOUVER — Some species of North American hummingbirds are in severe decline and a British Columbia research scientist says one possible cause might be the same insecticide affecting honey bees.

Christine Bishop with Environment and Climate Change Canada said researchers started looking at a variety of factors that may be responsible, ranging from habitat loss to changes when plants bloom.

To try and find some answers, researchers began collecting urine and feces from the birds for testing.

“No one has ever measured pesticides in hummingbirds before. So we decided to try it,” she said in an interview. “It turns out, to our surprise actually, that the birds are obviously picking up pesticides in their food, which can be nectar and also insects.”

Bishop said the concentration found in the urine is relatively high at three parts per billion.

“Now what does it mean? Right now we’re just understanding what the level of exposure is, and then how is it affecting the population, well that’s part of the population dynamics,” she said.

Her research is focused in the agricultural regions in the Fraser Valley and southern B.C. — the core area for the rufous hummingbird.

The rufous is a feisty, red-throated bird that weighs about as much as a nickel and spends its summers in B.C., Alaska and the Pacific Northwest states, then migrates to the southern United States and Mexico.

The testing doesn’t harm the birds. Researchers hang a net over a feeder and then lower it like a drape when the bird comes to feed.

Because the hummingbird is constantly processing nectar, it is also constantly expelling it, and Bishop said by the time they are banded the bird has likely expelled urine and feces to test.

The annual breeding bird survey shows that between 1966 and 2013, the rufous population on the Pacific Coast dropped an average of 2.67 per cent per year. The survey says the Allen’s and broad-tailed hummingbirds were also in decline.

Health Canada is re-evaluating the use of imidacloprid, a neonicotinoid insecticide used in on a large number of agricultural crops and at home on fleas or ticks on cats and dogs.

Health Canada says they are aware of Bishop’s work and will consider information she passed on during a consultation period as part of its re-evaluation. Health Canada says in its statement it expects to publish its findings in 2018.

A separate Health Canada preliminary report issued in 2013 says imidacloprid has potential for short-and long-term effects on bees, including a change in behaviour and mortality.

Bishop is two years into a five-year study and said the next question that needs to be answered is whether pesticides could be a factor in the decline of hummingbirds.

“We can’t rule it out,” she said.

Like bees, hummingbirds return to the same place to find food and they remember where certain flowers are, said Bishop, adding there are concerns pesticides might disrupt their memory.

But researchers don’t think the decline is strictly an agricultural issue.

It could be habitat loss, or seasonal plants blooming at the wrong time of year, or even an increase in the deer population with the animals eating the same flowers the hummingbirds need for their food source, Bishop said.

The population of the Anna’s hummingbird is also increasing in the area as the birds move north. Bishop said given the bird’s territorial and aggressive nature, it’s possible they are forcing the rufous out.

“But what’s interesting about this is … more and more people are putting out feeders, yet the population is still declining.”