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World’s wildlife population down by 68% since 1970

Great Indian bustard (Author - Prajwalkm) (CC BY-SA 3.0)

Great Indian bustard (Author – Prajwalkm) (CC BY-SA 3.0)

The WWF’s Living Planet Report 2020, released on 9 September 2020, has found that there has been a reduction of 68 per cent in the global wildlife population between 1970 and 2016. The report also found that 75 per cent of the the Earth’s ice-free land surface has already been significantly altered, most of the oceans are polluted, and more than 85% of the area of wetlands has been lost during this period.

The most important direct driver of biodiversity loss in the last several decades has been land-use change, primarily the conversion of pristine habitats into agricultural systems, while much of the oceans have been overfished.

The highest biodiversity loss due to land use change globally has been found in Europe and Central Asia at 57.9 per cent, then in North America at 52.5 per cent, Latin America and Caribbean at 51.2 per cent, Africa at 45.9 per cent and then Asia at 43 per cent.

Other factors leading to biodiversity loss include species overexploitation (like overfishing), invasive species and diseases, as well as pollution and climate change.

The largest wildlife population loss, according to the Living Planet Index, has been in Latin America at an alarming 94 per cent.

The report also finds that one of the most threatened biodiversity globally has been freshwater biodiversity, which has been declining faster than that in oceans or forests. Almost 90 per cent of global wetlands have been lost since 1700 and global mapping has recently revealed the extent to which humans have altered millions of kilometres of rivers.

India, a “megadiverse country” with over 45,000 species of plants in only 2.4 per cent of the world’s land area, has already lost six plant species to extinction, according to the IUCN Red List. The report further finds that India has lost nearly one-third of its natural wetlands to urbanisation, agricultural expansion and pollution over the last four decades and WWF India’s report on Water Stewardship for Industries revealed that 14 out of 20 river basins in India are already water stressed and will be moving to extreme water scarcity by 2050.

“The report indicates that our relationship with biodiversity and nature are unravelling. Even health of the soil is declining and we are losing the topsoil, including in India, at an alarming rate,” said WWF India programme director Sejal Worah.

Worah added that in India, adequate data, on different aspects regarding plant and animal species and their habitats, are simply not available. In the absence of this data, it also becomes more difficult to identify a problem and envisage a solution. (Indian Express)

Scientists explore the evolution of animal homosexuality —

Imperial researchers are using a new approach to understand why same-sex behaviour is so common across the animal kingdom.

In 1910, a team of scientists set off on the Terra Nova Expedition to explore Antarctica. Among them was George Murray Levick, a zoologist and photographer who would be the first researcher to study the world’s largest Adélie penguin colony. He chronicled the animals’ daily activities in great detail.

In his notebooks, he described their sexual behaviour, including sex between male birds. However, none of these notes would appear in Levick’s published papers. Concerned by the graphic content, he only printed 100 copies of Sexual Habits of the Adélie Penguin to circulate privately. The last remaining copy was recently unearthed providing valuable insights into animal homosexuality research.

But forays into animal homosexuality research long predate Levick, with observations published as far back as the 1700s and 1800s. More than 200 years later, research has moved past some of the taboos those early researchers faced and shown that homosexuality is much more common than previously thought.

Same-sex behaviour ranging from co-parenting to sex has been observed in over 1,000 species with likely many more as researchers begin to look for the behaviour explicitly. Homosexuality is widespread, with bisexuality even more prevalent across species.

Researchers are now going beyond just observing it though, with researchers at Imperial leading the way in unravelling how, and why, homosexuality is found across nature.

Case study: gentoo penguins

Overturning Darwin’s paradox

With this behaviour seen across species from birds and insects to reptiles and mammals – including humans – researchers are trying to understand why.

In the past, homosexual behaviour was often ignored because it supposedly contradicted Darwin’s theory of evolution. Scientists argued homosexuality was a sort of ‘Darwinian paradox’ because it involved sexual behaviour that was non-reproductive. Recent evidence however suggests homosexual behaviour could play important roles in reproduction and evolution.

Among the researchers leading the way is Vincent Savolainen, Professor of Organismic Biology at Imperial. Savolainen is a world-renowned evolutionary biologist who approaches many of the same questions Darwin did, but from a contemporary perspective. Savolainen’s contributions range from solving Darwin’s “abominable mystery” of flowering plants to elucidating how great white sharks evolved to be super-predatory fast-swimmers.

Savolainen explains: “I tackle big evolutionary biology questions. It doesn’t really matter what organism, at the end of the day it’s all about how genes have evolved either to produce a species or a new behaviour.”

The overarching aim of his lab can be summed up with the saying: “Nothing in biology makes sense except in the light of evolution.”

Savolainen has turned this philosophy to ‘Darwin’s paradox’. In 2016, Savolainen started some work on animal homosexuality, beginning with a chapter on the Evolution of Homosexuality. Since then, he has assembled a collaborative team of researchers to examine the question through field work, genomic sequencing and new theoretical models.

Case study: spider monkeys

Into the wild

On Imperial’s Silwood Park campus, Savolainen’s Ph.D. student Jackson Clive is spending some of his final days in the lab before he heads out for field work. It will be his second of many months-long trips to observe rhesus macaques in the wild. Female homosexuality has been well studied in Japanese macaques, but Clive’s research would examine how homosexual behaviour differs in males and across environments.

These trips are intense in many ways besides the physical challenges of the bush.

Clive explains: “Behavioural studies take a long time especially for these unpredictable and infrequent behaviours, which includes almost all sexual behaviours. You have to do a lot of sitting around and watching while also being quite alert. It takes quite a lot of effort to recognize these individual primates. In one social group I have to recognize 120 males individually.”

Before beginning his Ph.D. research, Clive was studying a family of mountain gorillas in East Africa. He noticed mounting between male gorillas, though that was not the main focus of his research at the time.

“It’s just wherever you look. I can give you papers on beetles, spiders, flies, fish, flamingos, geese, bison, deer, gibbons, bats – loads of bats, bats get up to all sorts,” he says. “The list is endless.”

It’s early days for the Imperial research team. Recording homosexual behaviour in the wild and collecting blood samples are the first steps for Clive; the next is sequencing DNA to search for connections between the behaviour and genetic markers.

Case study: scarab beetles

Beyond the ‘gay gene’

What does animal homosexuality look like biologically? It’s hard to say.

In 1993 there was a media frenzy over the discovery of the ‘gay gene’. This idea stemmed from a study showing a correlation between genetic marker Xq28 and male homosexuality, although there were statistical uncertainties about some of the findings.

Scientists have successfully modelled other complex or polygenic traits like height. There is not a single ‘tall’ or ‘short’. Instead, height is determined by changes across hundreds of genes in combination with environmental factors.

To understand what gives rise to complex traits and behaviours, researchers must identify where the genetic changes take place and what underlying processes are driving them. Then they can see what this should look like in the real world.The biological and hereditary factors of homosexuality are most certainly not tied to a single gene. Researchers aren’t searching for one genetic marker or one cause but a combination of factors that give rise to certain behaviours under specific circumstances.

To create models of homosexuality, Savolainen recruited Ewan Flintham as a Ph.D. student in evolutionary biology at Imperial. Flintham previously worked on models for speciation— the formation of new and distinct species in the course of evolution—as well as sexual behaviour in fruit flies.

He says: “We have the capacity to model complex behaviours and pull on massive amounts of data. However, creating a complex model isn’t beneficial unless it is modelling a useful concept.”

The bisexual advantage

There are many theories about why homosexuality is important for reproduction and evolution. Savolainen has outlined some leading models. One is the “bisexual advantage” model where animals with a more fluid sexuality are more likely to reproduce. Savolainen’s lab looks at a range of sexual behaviours from strict heterosexuality to homosexuality. Bisexuality may be “an evolutionary optimum phenotype in many species, including humans,” according to Savolainen’s review.

Other models consider whether a gene is beneficial for a specific sex. For example, if the gene were ‘feminizing’ in the sense that it would lead to females having more offspring so it would be passed on in spite of being disadvantageous for a male’s own reproduction, i.e. being homosexual. Meanwhile, others posit that homosexuality could also play a role in evolution through co-parenting or helping to raise relatives’ offspring. These explanations are not exclusive of one another, and it is likely that a combination of factors are important for the evolution of homosexuality.

With these new models, researchers can test many theories in combination and vary the data inputs accordingly. The “golden standard” would use the original genetic and behavioural data from the macaque field work and fit them to different theories to see how each could be applied to other populations and animals.

The primates Savolainen’s lab is currently studying are of course closely related to humans. Studying non-human primates is helpful because it provides clearer data and separates the behaviour from culture while at the same time offering new insights on human sexuality and evolution.

Case study: grey headed flying boxes

A human connection

Ph.D. student Tom Versluys is looking directly at humans, specifically by studying mate choice in couples. His previous research examined how body-to-limb ratio makes men more attractive. In Savolainen’s lab, he’s taking a broader and more technical approach. He will create 3-D face models of couples to compare shape, structure, and proportions. Ultimately, the project will combine questionnaires, facial modelling and genetic sequencing to examine similarities between couples and investigate whether mate-choice decisions are being driven by considerations of biological or social compatibility.

Importantly, this will include exploration of homosexual partners in the hope of understanding different mate-choice strategies in reproductive and non-reproductive contexts. Versluys is currently recruiting heterosexual and homosexual couples among Imperial students and staff for his research. If you would like to know how similar you and your partner are (or would just like 3-D models of your faces), please get in touch with him at tmv3318@ic.ac.uk.

Reframing homosexuality

Versluys says: “Homosexuality is still something that’s not always well understood among the scientific community and maybe even more poorly understood among the general population. It’s currently being reframed, in our lab and elsewhere, as a normal behaviour rather than something that’s abhorrent or problematic.”

The hope is that as homosexuality is better understood, research will dispel people’s misconceptions. However, many of the historical cultural challenges persist. And despite the acknowledgement of how widespread homosexuality is in nature, researchers have to contend with a dearth of research that should have been built up over decades.

Savolainen explains: “It’s still risky and unusual research that is difficult to support through traditional funding routes. We’re looking for organizations or individuals that believe in this research and are willing to take that risk.” (Phys.org)

Australia Wants to Build a Huge Concrete Runway in Antarctica. Here’s Why That’s a Bad Idea —

 

A colony of Adelie Penguins

A colony of Adelie Penguins

Australia wants to build a 2.7-kilometre concrete runway in Antarctica, the world’s biggest natural reserve. The plan, if approved, would have the largest footprint of any project in the continent’s history.

The runway is part of an aerodrome to be constructed near Davis Station, one of Australia’s three permanent bases in Antarctica. It would be the first concrete runway on the continent.

The plan is subject to federal environmental approval. It coincides with new research published in July (2020) showing Antarctica’s wild places need better protection. Human activity across Antarctica has been extensive in the past 200 years – particularly in the coastal, ice-free areas where most biodiversity is found.

The area around Davis Station is possibly Antarctica’s most significant coastal, ice-free area. It features unique lakes, fjords, fossil sites and wildlife.

Australia has successfully operated Davis Station since 1957 with existing transport arrangements. While the development may win Australia some strategic influence in Antarctica, it’s at odds with our strong history of environmental leadership in the region.

Year-Round Access

The Australian Antarctic Division (AAD), a federal government agency, argues the runway would allow year-round aviation access between Hobart and Antarctica.

Presently, the only Australian flights to Antarctica take place at the beginning and end of summer. Aircraft land at an aerodrome near the Casey research station, with interconnecting flights to other stations and sites on the continent. The stations are inaccessible by both air and ship in winter.

The AAD says year-round access to Antarctica would provide significant science benefits, including:

  • Better understanding sea level rise and other climate change impacts
  • Opportunities to study wildlife across the annual lifecycle of key species including krill, penguins, seals and seabirds
  • Allowing scientists to research through winter.

Leading international scientists had called for improved, environmentally responsible access to Antarctica to support 21st-century science. However, the aerodrome project is likely to reduce access for scientists to Antarctica for years, due to the need to house construction workers.

Australia: An Environmental Leader?

Australia has traditionally been considered an environmental leader in Antarctica. For example, in 1989 under the Hawke government, it urged the world to abandon a mining convention in favour of a new deal to ban mining on the continent.

Australia’s 20 Year Action Plan promotes “leadership in environmental stewardship in Antarctica”, pledging to “minimise the environmental impact of Australia’s activities”.

But the aerodrome proposal appears at odds with that goal. It would cover 2.2 square kilometres, increasing the total “disturbance footprint” of all nations on the continent by 40%. It would also mean Australia has the biggest footprint of any nation, overtaking the United States.

Within this footprint, environmental effects will also be intense. Construction will require more than three million cubic metres of earthworks – levelling 60 vertical metres of hills and valleys along the length of the runway. This will inevitably cause dust emissions – on the windiest continent on Earth – and the effect of this on plants and animals in Antarctica is poorly understood.

Wilson’s storm petrels that nest at the site will be displaced. Native lichens, fungi and algae will be destroyed, and irreparable damage is expected at adjacent lakes.

Weddell seals breed within 500 metres of the proposed runway site. Federal environment officials recognize the dust from construction and subsequent noise from low flying aircraft have the potential to disturb these breeding colonies.

The proposed area is also important breeding habitat for Adélie penguins. Eight breeding sites in the region are listed as “important bird areas”. Federal environment officials state the penguins are likely to be impacted by human disturbance, dust, and noise from construction of the runway, with particular concern for oil spills and aircraft operations.

The summer population at Davis Station will need to almost double from 120 to 250 during construction. This will require new, permanent infrastructure and increase the station’s fuel and water consumption, and sewage discharged into the environment.

The AAD has proposed measures to limit environmental damage. These include gathering baseline data (against which to measure the project’s impact), analysing potential effects on birds and marine mammals and limiting disturbance where practicable.

But full details won’t be provided until later in the assessment process. We expect Australia will implement these measures to a high standard, but they will not offset the project’s environmental damage.

Playing Politics

So given the environmental concern, why is Australia so determined to build the aerodrome? We believe the answer largely lies in Antarctic politics.

Australian officials have said the project would “contribute to both our presence and influence” on the continent. Influence in Antarctica has traditionally corresponded to the strength of a nation’s scientific program, its infrastructure presence and engagement in international decision-making.

Australia is a well-regarded member of the Antarctic Treaty. It was an original signatory and claims sovereignty over 42% of the continent. It also has a solid physical and scientific presence, maintaining three large year-round research stations.

But other nations are also vying for influence. China is constructing its fifth research station. New Zealand is planning a NZ$250 million upgrade to Scott Base. And on King George Island, six stations have been built within a 5km radius, each run by different nations. This presence is hard to justify on the basis of scientific interest alone.

Getting Our Priorities Straight

We believe there are greater and more urgent opportunities for Australia to assert its leadership in Antarctica.

For example both Casey and Mawson stations – Australia’s two other permanent bases – discharge sewage into the pristine marine environment with little treatment. And outdated fuel technology at Australia’s three stations regularly causes diesel spills.

At Wilkes station, which Australia abandoned in the 1960s, thousands of tonnes of contaminants have been left behind.

Australia should fix such problems before adding more potentially damaging infrastructure. This would meet our environmental treaty obligations and show genuine Antarctic leadership. (This article is written by — Shaun Brooks who is a University Associate at the University of Tasmania. Julia Jabour is an Adjunct Senior Lecturer at the University of Tasmania)

Sparrows’ storm stress a harbinger of climate-change impact —

White-throated sparrow (CC BY-SA 3.0) (Author - Cephas)

White-throated sparrow              (CC BY-SA 3.0)                     (Author – Cephas)

Sparrows show increased stress when exposed to more numerous and more severe winter storms, says a Western study that tested the songbirds’ resilience to the effects of climate change.

And where a canary in a coal mine once provided an early signal of danger to humans below ground, “sparrows in a snowstorm” might be a harbinger of trouble for other species dealing with frequent extreme-weather events, the researchers say.

The paper, recently published in Frontiers in Ecology and Evolution, was co-authored by Ph.D. student Andrea Boyer and Scott MacDougall-Shackleton, director of the Advanced Facility for Avian Research (AFAR) at Western.

Theirs is the first study to simulate, in a controlled setting, the impact of winter storms on birds. “This is one of the few places in the world you can do a study like this,” because of the facility’s unique capacity to mimic different climate conditions, MacDougall-Shackleton said.

The study showed that white-throated sparrows exposed to one storm a week increased their bodies’ energy stores as a survival mechanism; and two storms per week depleted the songbirds’ ability to add to, or draw upon, their energy reserves.

The white-throated sparrows’ breeding grounds are in boreal forests in Canada’s high north and their winter range is as far south as Florida, Boyer said.

The study showed sparrows can ‘predict’ an impending storm by somehow detecting a drop in barometric pressure — and they will rapidly put on fat and body mass in preparation for it. This creates a metabolic and physiological reserve they can draw upon if a protracted storm leaves them unable to forage for food.

But more frequent storms strain their metabolic and physiological resilience.

In this study, one group of sparrows was exposed to a drop in barometric pressure and a 10-degree drop in temperature (to just above freezing) for eight hours, once a week for nine weeks: a dramatic but realistic simulation of a weekly winter storm.

The once-a-week-storm birds put on body weight and fat to deal with the upcoming windless “storm.”

They adapted.

But in a second series of tests on a different group of sparrows, the storms took place twice a week and the birds were not as resilient.

Although they ate more than the control group, they expended that food energy in the moment. They had lower fat stores, less weight gain and therefore lower energy reserves.

“The birds remained healthy in the second study, but they couldn’t put on the fat and body mass—they couldn’t rely on their ‘insurance policy’ of extra fat,” MacDougall-Shackleton said.

“In the wild, if a bird isn’t able to put on that extra storage, they wouldn’t be able to recharge and they’re at higher risk of starvation,” he said.

(In both trials, the birds were fed well during and after the storm.)

Boyer said these birds are naturally quite storm-resilient, so the study results are troubling. “We’re throwing these challenges at them and then it becomes a question of whether they can cope, whether they can adapt.”

As a sentinel species, the sparrows could also help us understand how other birds and other animals would fare in a world with more severe, more frequent storms.

That’s particularly important as massive storms that used to be expected every 20 years are now occurring multiple times in a season.

“A lot of people think about climate change as temperature change and sea levels rising,” MacDougall-Shackleton said, “but what many people don’t think about as often is the increasing frequency and intensity of storms, which could have an effect on wildlife.

This is the first study to gage birds’ responses to storms in a lab with controlled temperature and barometric pressure—a distinct advantage over studies limited to examining how birds in the wild respond to storms.

Boyer has an undergraduate degree in biology/ecology and meteorology and her graduate work combined the two. “I saw the Western (AFAR) wind tunnel and thought this could be used as a weather chamber. It had never been used for that before.”

Researchers at AFAR ordinarily study bird reproduction, migration, over-wintering, flight and communication under different environmental conditions but, until now, have not combined that with meteorological work.

Boyer said these birds’ responses may also influence biodiversity. “You’ll see populations that will, in the future, slowly be declining because they won’t be able to handle extreme weather conditions.” (Phys.org)

A cheap, ingenious trick to save forty-spotted pardalote from blood-sucking maggot – it worked —

Saving endangered species from extinction is a challenging job that requires creative, affordable and effective interventions. In a rare good news story for conservation, we came up with one such method.

We want to save the forty-spotted pardalote – an extremely rare Tasmanian bird about the size of a ping pong ball. The few remaining individuals are at risk from an unusually harmful threat: blood-sucking fly larvae.

Forty-spotted Pardalote

Forty-spotted Pardalote

These parasitic flies search out the nests of pardalotes to feed on their defenseless young. The moment a pardalote chick hatches from its egg, the fly maggots burrow into its skin to drink its blood. The parasite kills nine out of every ten chicks in some areas.

We needed a way to ward off the parasites. As our new research shows, we made one – using chicken feathers and everyday items you’d find in any hardware store. The results show that with a bit of creative thinking and expert knowledge, vulnerable species can be protected.

An imperilled songbird

Forty-spotted pardalotes are olive-green songbirds with two rows of white dots along their wings. Deforestation has caused their local extinction across much of mainland Tasmania. The birds survive mostly on islands off the east coast in numbers that vary according to habitat quality.

They forage predominantly in the foliage of white gums (Eucalyptus viminalis) for manna, a sweet crystallised form of tree sap. Many Australian birds feed on manna, but forty-spotted pardalotes are unique because theyfarmit – using their beaks to make tiny nicks in leaves and stems to stimulate manna production.

But parasitic flies are threatening the survival of these remarkable little birds. The maggots of these flies, known formally as Passeromyia longicornis, bore into exposed skin of featherless chicks and feed on their blood. Unsurprisingly, as the maggots grow fat, the chicks suffer and usually die. Small birds are killed quickly when infested with large numbers of blood-sucking maggots.

A novel solution

We wanted to find an effective way to help protect pardalotes from fly-strike. The solution also needed to be cheap, to improve the odds that land managers can help pardalotes over large areas in the long term.

Using creative thinking and our detailed knowledge of pardalotes, we devised a plan.

Pardalotes love to make a soft, warm nest lined with stray feathers of other birds they find on the forest floor. But finding feathers is hard, time-consuming work. We decided to supply those feathers, but with an added bonus.

We took sterilised chicken feathers (available in pet stores for canaries to build their nests) and laced them with a bird-safe insecticide that would ward off the parasites. Using scrap wire, duct tape and round plastic trays (the kind used under pot plants), we built “self-service” feather dispensers and deployed them in the forests where pardalotes were building nests.

It didn’t take the pardalotes long to find this bonanza of free building materials – our dispensers were as busy as the toilet paper aisle during a pandemic! Some birds built their nests mostly out of our medicated feathers.

And now for the best part: the survival of chicks dramatically improved in the nests built with insecticide-treated feathers. On average, 95% of chicks from these birds survived, compared with only 8% of birds that used feathers without insecticide.

This more than tenfold increase in nest survival came with very little effort on our part. We just provided the feather dispensers, and the pardalotes did the rest.

Understanding the species

Parasites can become an existential threat when the populations of their hosts become very small. But it’s important to note that parasites are a natural part of the ecosystem and have their own intrinsic value. Eliminating them entirely can create unexpected new problems – and that is not our aim.

Passeromyia maggots have been recorded in other small birds in our study area. This means there are plenty of other more abundant host birds for the flies to feed on, without adding to the problems that endangered forty-spotted pardalotes already face.

Our work has shown that by understanding how species live, it’s possible to exploit their natural behaviour to provide targeted protection from threats such as parasites.

Combining good ecological data with clever problem-solving is a crucial skill for natural resource managers. Managing the global extinction crisis will require more innovative solutions like this. (The Conversation)

Bird beaks did not adapt to food types as previously thought, study suggests —

Various shapes of birds' beaks (InfoVisual.info site)

Various shapes of birds’ beaks (InfoVisual.info site)

A study, led by the University of Bristol, has shed some new light on how the beaks of birds have adapted over time.

The observation that Galapagos finch species possessed different beak shapes to obtain different foods was central to the theory of evolution by natural selection, and it has been assumed that this form-function relationship holds true across all species of bird.

However, a new study published in the journal Evolution suggests the beaks of birds are not as adapted to the food types they feed on as it is generally believed.

An international team of scientists from the United Kingdom, Spain and the US used computational and mathematical techniques to better understand the connection between beak shapes and functions in living birds.

By measuring beak shape in a wide range of modern bird species from museum collections and looking at information about how the beak is used by different species to eat different foods, the team were able to assess the link between beak shape and feeding behaviour.

Professor Emily Rayfield, from the University of Bristol’s School of Earth Sciences, and senior author of the study, said: “This is, to our knowledge, the first approach to test a long-standing principle in biology: that the beak shape and function of birds is tightly linked to their feeding ecologies.”

Guillermo Navalón, lead author of the study and a final year Ph.D. student at Bristol’s School of Earth Sciences, added: “The connection between beak shapes and feeding ecology in birds was much weaker and more complex than we expected and that while there is definitely a relationship there, many species with similarly shaped beaks forage in entirely different ways and on entirely different kinds of food.

“This is something that has been shown in other animal groups, but in birds this relationship was always assumed to be stronger.”

Co-author, Dr. Jesús Marugán-Lobón from Universidad Autónoma de Madrid, said: “These results only made sense when you realise birds use the beak for literally everything!

“Therefore, also makes sense they evolved a versatile tool not just for getting food, but also to accomplish many other tasks.”

The study is part of a larger research effort by the team in collaboration with researchers from other universities across Europe and the US to better understand the main drivers of the evolution of the skull in birds.

Dr. Jen Bright, co-author from the University of South Florida, said: “We have seen similar results before in birds of prey, but this is the first time we studied the link between beak shape and ecology across all bird groups.

“We looked at a huge range of beak shapes and feeding ecologies: hummingbirds, eagles, parrots, puffins, flamingos, pretty much every beak you can think of.”

Guillermo Navalón added: “These results have important implications for the study of fossil birds.

“We have to be careful about inferring ecology in ancient birds, which we often assume based solely on the shape of the beak.

“Really, we’re just starting to scratch the surface, and a lot more research is needed to fully understand the drivers behind beak shape evolution.” (journal – ‘Evolution’)

Escaped pet parrots are now naturalized in 23 US states, study finds —

When Stephen Pruett-Jones, Ph.D., an ecologist at the University of Chicago, first came to Chicago in 1988, he stumbled on a unique piece of the city’s history: the monk parakeets of Hyde Park.

The squat, bright-green birds aren’t native to Illinois, or the United States at all. The U.S. originally had two native parrot species: the Carolina parakeet and the thick-billed parrot. The Carolina parakeet is now extinct; the thick-billed parrot, a Mexican species that ranged into the southwestern states, was driven out of the U.S.

In the 1950s and 60s, tens of thousands of monk parakeets were imported from South America as pets. Inevitably, many of them escaped or were released. By 1968, they were found breeding in the wild across 10 states, including a colony in the Hyde Park neighborhood of Chicago, home of the University of Chicago campus.

Pruett-Jones, who usually studies wrens and other wild birds in Australia, noticed a large group of the parakeets on his daily commute. He started sending students out to study the birds and eventually organized an annual lab project to count them.

“I have never actually held a wild parrot in the United States,” he said. “But indirectly I’ve become the spokesperson for parrot research here because when I saw the monk parakeets in Chicago, I realized nobody else was working on them.”

Those monk parakeets aren’t the only parrot species thriving in the U.S. as a result of the pet trade. In a study, Pruett-Jones teamed up with Jennifer Uehling, a former UChicago undergraduate student now working on a Ph.D. at Cornell University, and Jason Tallant of the University of Michigan to research data on bird sightings from 2002 to 2016. They found that there were 56 different parrot species spotted in the wild in 43 states. Of these, 25 species are now breeding in 23 different states.

“Many of them were escaped pets, or their owners released them because they couldn’t train them or they made too much noise—all the reasons people let pets go,” Pruett-Jones said. “But many of these species are perfectly happy living here and they’ve established populations. Wild parrots are here to stay.”

A diverse new landscape for parrots

The study, published in the Journal of Ornithology, uses two different databases of bird sightings to track this diverse new landscape of naturalized parrot species. The first, the Christmas Bird Count, is an annual survey organized by the National Audubon Society that captures a snapshot of birds in the U.S. during a two-week period from December 14 to January 15 each year. The second resource, eBird, is an online database for bird watching enthusiasts to log all the birds they have seen.

Once Uehling, Tallant, and Pruett-Jones compiled the data, the most common species were monk parakeets, the Red-crowned Amazon, and the Nanday Parakeet. Most of these birds are concentrated in the warmer climates of Florida, Texas and California, but there are other large populations concentrated around cities like New York and Chicago. Pruett-Jones says there are now more Red-crowned Amazons living in California than there are in their original habitats in Mexico.

“The entire conservation focus for this species is now on a non-native, introduced, naturalized population,” he said. “The survival of the species is most likely going to come from efforts to save it someplace where it never existed before.”

Monk parakeets are reported to be agricultural pests in South America, but other than a few isolated examples, there is no evidence that any of the feral parrots in the U.S. are invasive or competing with native birds. Monk parakeets are the only species of parrot that build their own nests, however, and the bulky structures are known to damage utility lines.

Good luck talisman

The story of Chicago’s parakeets is one with the city, that of tenacious survival in spite of the elements. Most of the year they feed by foraging in parks and open grassy areas. They don’t migrate, but one of Pruett-Jones’ students discovered that they survive Chicago’s harsh winters by switching almost exclusively to backyard bird feeders from December to February.

Harold Washington, Chicago’s first African American mayor, lived across the street from one of the city’s best-known parakeet colonies and called them a “good luck talisman.” After he died in 1987, the USDA tried to remove the birds, but local residents threatened a lawsuit.

The parakeets stayed but their numbers have dwindled from a peak of about 400 birds to just 30 today. Some of the them have dispersed to greener areas in the suburbs, although the largest colony is now under the Skyway bridge connecting Illinois to Indiana. There are also signs of a nationwide decline in all birds, perhaps due to a disease or parasite.

Pruett-Jones may have become a national expert on parrots by accident, but he says this work is crucial to understand conservation of endangered species and how non-native or invasive species can spread.

“Because of human activity transporting these birds for our own pleasure, we have inadvertently created populations elsewhere,” he said. “Now for some of these parrots, they may become critical to the survival of the species.” (Phys.org)

Secrets of flocking by birds and fish revealed —

Watching thousands of birds fly in a highly coordinated, yet leaderless, flock can be utterly baffling to humans. Now, new research is peeling back the layers of mystery to show how exactly they do it — and why it might be advantageous to fly right.

Mathematical models show that the birds’ complicated collective behavior can be the consequence of a few simple rules of the road — or sky.

“Initially in [the] 1930s, people thought it might be telepathy that guided flocks of birds. Now we know self-organization is at the heart,” said Charlotte Hemelrijk of the University of Groningen in the Netherlands.

Flock of Auklet

Flock of Auklet

Hemelrijk has studied schools of fish and flocks of starlings — birds that can gather in flocks as large as 30,000 individuals.

“Each day they flap around for 30 minutes in the evening before sleep, and it’s just spectacular the way they do this,” Hemelrijk said.

And while fish generally only made long skinny shapes as they swam, the shapes that the bird flocks could take — elongated, bulbous, hourglass, and constantly shifting — were incredibly diverse. This motivated Hemelrijk to work, collaborating with a computer programmer to create a new model that figured out the underlying logic of the starlings’ flight.

She found that even in giant flocks, each bird maintained just about the same speed and only interacted with about seven neighbors as it swooped and dove. As the birds rolled through a turn, the shape of the flock changed from wide and flat to long and narrow. Additionally, birds that are flying abreast each other end up in a single file line when they turn. The research was published in the journal PLoS One.

The benefits of flocking are still being determined. In one study that measured the heart rate of pigeons, birds consumed more energy when they were forced to fly closer to each other.

“Clearly for some birds, flying together is costing them energy, so the question remains: why do they do it?” said Geoffrey Spedding, a professor of mechanical and aerospace engineering at University of Southern California. “It could be that flocking is a social phenomenon as well as mechanical one — something like getting on the treadmill at lunch for exercise.”

Spedding said that the study of flocking can be applied to lots of other fields.

“Suppose I want to make a flock of flying machines that can sense an environment and manage coordination among individuals. A good place to start would some rules of interaction in birds that can equally apply to our artificial devices,” Spedding said.

Gathering in flocks could also raise the overall intelligence of the group. According to a study in the Proceedings of the National Academy of Sciences, larger groups of great and blue tits are better at solving problems than smaller ones.

“For one thing, when there are more birds around, each bird doesn’t have to be as vigilant for predators, so they can devote more attention to the task,” said Julie Morand-Ferron, a researcher at Oxford University’s zoology department.

Social birds can learn quickly from each other, so having one whiz kid present among the group can improve the situation for everyone. In the experiments, the researchers created a lever-pulling device that the birds had to operate to get a food reward. They found that as the size of the groups increased individual birds got more food in return for the time they spent mastering the device.

Morand-Ferron said it’s not clear if larger groups work better for all types of birds, but that several species have had the same outcomes.

“Technical innovation is a new benefit to flocking that had not been described in the wild before,” Morand-Ferron said. (Phys.org)

Female warblers live longer when they have help raising offspring —

Seychelles warbler (CC BY-SA 3.0) (Author - Remi Jouan)

Seychelles warbler (CC BY-SA 3.0)             (Author – Remi Jouan)

Death is, unfortunately, an inevitable consequence of life. In most animals growing old is accompanied by progressive deterioration in health and vitality, leading to an increasing likelihood of death with age.

However, within populations of a single species there is lots of variation in when individuals start to deteriorate in later life. Why some individuals of the same species age faster than others is one of the biggest unanswered questions in biology. It’s also one that has massive implications for healthcare and society. Understanding why individuals age differently may allow us to promote longer and healthier lifespans in humans and other animals.

The environment that an individual experiences as it strives to survive and reproduce appears to be a major driver of individual variation in ageing. We are all familiar with the idea that some people look like they have “had a hard life”, while others are “young for their age”. Scientists and medics sometimes refer to an individual’s biological age. An individual has a biological age of 70 if their health and condition resembles that which we would expect of a 70 year old – whatever their actual age is.

It’s thought that a lot of this variation in ageing originates because individuals experience different levels of physiological stress as they go through life. We now need to figure out which factors explain these differences, at what point they have an effect in the course of a life, and how they can be avoided or mitigated.

Research on a small bird could help us understanding this process of ageing – and the unlikely benefits of childcare.

How our cells record ageing

Investigating the causes of ageing within natural populations – where individuals are exposed to realistic variation in stresses and do not benefit from any intervention or medication – is important, but very tricky. Wild living individuals have to be tracked throughout their lives to assess the environmental and social conditions they experience, and their subsequent health and survival.

Our long-term study of the Seychelles warbler (Acrocephalus sechellensis), also known as Seychelles brush warbler – a small, tropical songbird – on the island of Cousin in the Indian Ocean is a useful case study for understanding the ageing process. Since the 1990s, all the warblers on this tiny island – just 40 football fields in size – have been fitted with coloured leg rings so they can be tracked and identified. Birds don’t disperse on or off this isolated island so we were able to follow them from birth to death. We also monitored their health, reproduction and survival, which all decline rapidly in elderly individuals.

We also measured the warbler’s telomeres – repetitive DNA sequences which protect the ends of chromosomes but shorten in response to physiological stress. Telomere shortening has been shown to be a useful marker of biological condition and ageing in various animals, including humans. In the Seychelles warbler, telomere length predicts future survival. By measuring the telomere shortening that occurs in response to any given experience we can determine the impact that specific factors have on ageing.

Our previous studies on the Seychelles warbler have already found that certain factors influence the rate at which individuals age. For example, having a territory surrounded by unrelated and unfamiliar neighbours leads to more territorial fights, and hence more rapid telomere shortening. Growing up in a territory with limited food availability also has a detrimental impact on later ageing.

Our recent paper in Nature Communications has focused on how raising offspring is stressful and may lead to premature ageing – something that may not surprise many parents. Due to a lack of space on Cousin, many adults can’t find a territory in which to pair up and breed. Instead, these individuals may join up as subordinates to a dominant breeding pair within an already established territory – often the one in which they were born. They then sometimes help the dominant breeding pair raise their next batch of offspring—a process known as “cooperative breeding“.

Our analyses showed that the dominant birds that receive help have less telomere shortening than those that are left to do all of the parenting work themselves. This help also results in better survival of the dominant females. Therefore, we can see that the help that the dominant breeding birds received reduced the stress of breeding and delayed ageing, at least in females. The dominant males don’t appear to benefit from receiving help as much, probably because in the Seychelles warbler males invest much less energy in raising chicks than females do.

Our study confirms a long-held hypothesis that cooperative breeding – which is the norm in humans – can reduce the health costs to parents of raising young and may, therefore, slow down ageing. This could explain why more social species tend to have longer life-spans.

Our findings in the Seychelles warbler have identified the costs of more rapid ageing in overworked parents. These costs, and how individuals differ in what they experience and when, can help explain why there is so much variation in how individuals age in later life. (Phys.org)

Invasive plants are dyeing woodpeckers red —

Northern flicker pair - female (left), male (right)(Author - David Margrave)

Northern flicker pair – female (left), male (right)(Author – David Margrave)

An ornithological mystery has been solved! Puzzling red feathers have been popping up in eastern North America’s “yellow-shafted” population of Northern Flickers, but they aren’t due to genes borrowed from their “red-shafted” cousins to the west, according to a study in The Auk: Ornithological Advances. Instead, the culprit is a pigment that the birds are ingesting in the berries of exotic honeysuckle plants.

The Northern Flicker comes in two varieties—the birds of the west have a salmon pink or orange tinge to the undersides of their wings, while the eastern birds are yellow. Where the two populations meet in the middle, they frequently hybridize, producing birds with a blend of both colors. For years, however, flickers far to the east of the hybrid zone have been popping up with red-orange wing feathers. The prevailing explanation has been that they must somehow have genes from the western population, but Jocelyn Hudon of the Royal Alberta Museum and his colleagues have determined that the eastern birds’ unusual color actually has a different source: a pigment called rhodoxanthin, which comes from the berries of two species of invasive honeysuckle plants.

Hudon and his colleagues used spectrophotometry and chromatography to show that rhodoxanthin, rather than the type of carotenoid pigment that colors western red-shafted birds, was present in the feathers of yellow-shafted flicker specimens with the aberrant red coloration. Data from a bird-banding station helped confirm that the birds acquire the red pigment during their fall molt about early August, which coincides with the availability of ripe honeysuckle berries. The honeysuckles have also been implicated as the source of unusual orange feathers in Cedar Waxwings.

“At one point considered valuable wildlife habitat and widely disseminated, the naturalized Asian bush honeysuckles are now considered invasive and undesirable in many states. This is clearly not the last we have heard of aberrantly colored birds,” says Hudon. “The ready availability of a pigment that can alter the coloration of birds with carotenoids in their plumages could have major implications for mate selection if plumage coloration no longer signaled a bird’s body condition.”

“This is the pinnacle of a lengthy series of papers on the pigments deposited in primary feathers. Hudon et al. make use of the most up-to-date spectrometric and biochemical analyses to identify and quantify the pigments,” according to Alan Brush, an expert on feather color and retired University of Connecticut professor who was not involved with the study. “In addition to demonstrating that the red pigments in the molting yellow-shafted feathers are derived from their diets, not the result of interbreeding with the red-shafted form, they illuminate the dynamic nature of pigment deposition during molt, an accomplishment in itself.” (Phys.org)