Tag Archives: birds

Move aside, Justin Bieber. Bird sounds just dropped you off the chart

It’s an unusual year for Australian music charts. An album made entirely of tweets and squawks from endangered bird species has entered the top five, surpassing the likes of Michael Bublé, Mariah Carey, and Justin Bieber to reach one of the top positions. Called Songs of Disappearance, the album features the songs of 53 threatened species, with all proceedings donated to BirdLife.

The regent honeyeater. Image credit: Creative Commons.

The album is the result of a collaboration between BirdLife, David Steward (who has recorded sounds of Australian birds during the last four decades), and the Bowerbird Collective – a project by performers Simone Slattery and Anthony Albrecht to explore the connection between art and science through a multimedia platform. Apparently, it’s quite the hit.

“The title track celebrates the incredible diversity of the Australian soundscape, and highlights what we stand to lose without taking action. Be immersed in a chorus of iconic cockatoos, the buzzing of bowerbirds, a bizarre symphony of seabirds, and the haunting call of one of the last remaining night parrots,” the album’s website reads. 

Songs Of Disappearance is the first album of its type to appear in the top 10 of Australia’s Aria chart. It has already sold over 3,000 copies, including sounds from extremely rare species from Australia such as the regent honeyeater (Anthochaera phrygia) and the night parrot (Pezoporus occidentalis).

The album is currently fifth in Australia, just behind Adele’s 30, Ed Sheeran’s =, Paul Kelly’s Christmas Train, and Taylor Swift’s Red. The rest of the top 10 is formed by ABBA’s Voyage, Michael Bublé’s Christmas, Olivia Rodrigo’s Sour and Doja Cat’s Planet Her. The ranking changes every week. Needless to say, Songs of Disappearance is the first non-human entry on the list.

Birds under threat

As heartwarming as the album is, the situation of these birds is anything but uplifting.

A once-in-a-decade study published this month found that one in six Australian birds are currently threatened, with the climate crisis pushing species closer to extinction. Researcher Stephen Garnett of Charles Darwin University found that 216 out of 1,299 species are threatened – more than the 195 that were under threat back in 2011. 

Of the 216 endangered birds, 87 were listed as vulnerable, 74 as endangered, 32 as near-threatened, 21 as critically endangered, and two as possibly extinct. The study found that 96 species are doing worse than a decade ago, listing them on a higher threat category. There were also 23 birds that are doing better and were downlisted.

Among the new birds under threat, the researchers identified 17 that live in cooler, higher-elevation rainforests in Queensland. The list includes the fernwren (Oreoscopus gutturalis), whose numbers have dropped almost 60% since 2000, the golden bowerbird (Prionodura newtoniana), and the Victoria’s riflebird (Ptiloris victoriae). 

The study, known as the Action Plan for Australia’s Birds, found that global warming and the extreme weather events that it triggers such as bushfires were a key factor in the growing threat to Australia’s birds. The country was severely hit by bushfires a year ago, especially the New South Wales state, with over one billion trees that were burnt.

What’s the difference between a raven and a crow?

Although these two terms are used interchangeably, these two species are not the same. Although the differences between them are subtle, we can learn to tell the two apart. So let’s get to it!

Image via Pixabay.

Ravens and crows are closely related. They both belong to the Corvus genus of the Corvidae family of birds. Outwardly, they’re very similar — both are jet black and share several morphological features. Their natural ranges also have a lot of overlap, so they’re often seen (and mistaken for one another) in the same areas of the world.

Here is where the terms get a bit muddy, however. “Crow” is often used as a catch-all term for any bird in the genus Corvus. At the same time, people tend to refer to any larger bird from this genus as a “raven”. Taken together, it’s easy to see why very few people seem to be able to describe with any real detail what truly differentiates these species.

But — lucky you! — we’re about to go through them today.

Crow or raven?

One of the first indications that you’re seeing a crow rather than a raven is that the former generally travels in large groups, while the latter prefers to hang out in pairs. If we happen upon a solitary bird, however, such context clues won’t do us much good; so we’ll have to look at the characteristics of the individual.

Common ravens (Corvus corax) are, indeed, larger than your average crow. This is especially useful to know in rural areas, where size can be a pretty reliable indicator of which of these birds you’re dealing with. Ravens aren’t particularly fond of urban areas and their bustling crowds, however, so if you’re in a city, you’re probably more likely to be seeing a ‘really big crow’ than a raven. As a rule of thumb, crows are about the size of a pigeon and weigh on average 20 oz / o.55 kgs, while ravens are roughly as large as hawks, typically weighing 40 oz / 1.1 kgs.

A stuffed common raven and carrion crow, side by side, at the Natural History Museum of Genoa. Image via Wikimedia.

Meanwhile “crows” — typically the Carrion Crow (Corvus corone) in Europe and American Crow (Corvus brachyrhynchos) in the U.S. — are quite fond of cityscapes and generally not people-shy.

The two species also produce different sounds. Crows vocalize through ‘caw’s or ‘purr’s (sound sample for carrion crows, American crows) while ravens use much lower, rougher croaks. Personally, I find the latter to sound much more ominous, and use this as a rough but reliable guideline when trying to identify ravens.

If vocalizations are not forthcoming, either, we can start looking at the physical features of the birds in question. As far as the plumage is concerned, both species sport jet-black feathers. Raven feathers are very glossy with green, blue, and purple iridescence; they can also have a wet or oily sheen. Crow feathers are iridescent blue and purple but are far less shiny than those of ravens (although they still do have a little bit of sheen to them).

Ravens have larger and curvier beaks than crows. Both sport bristles at the base of the beak, but for ravens, these are much more pronounced. Ravens tend to have ruffled feathers on the throat, whereas crows’ are swept neat and tidy.

On the ground, both birds behave similarly. One reliable way to tell a raven apart here, however, is by how they walk: ravens tend to mix little hops in their gait when moving more rapidly. At a slow pace, a raven’s walking pattern is the same as those employed by crows.

If you happen to spot the birds mid-flight, a few more tell-tale differences become apparent. A raven’s wingspan is much greater than that of a crow (3.5-4 ft / 1-1.2 m and 2.5 ft / 76 cm, respectively) and raven’s wing beats make a distinctive swishing sound while a crow’s are silent. In flight, the raven’s neck is also longer than a crow’s. Crows tend to actively flap their wings more often than ravens, which tend to prefer soaring on rising masses of air (they are heavier, and this helps them save energy). If you see such a bird soaring — gliding along with outstretched wings — for more than a few seconds at a time, chances are it’s a raven.

Ravens like to do all sorts of fancy acrobatics during flight, including somersaults (loops) or even flying upside-down, possibly just for fun. Such behavior is a dead giveaway that you’re looking at a raven, but it’s not very reliable; they tend to only engage in such playful behavior on windy days, or those with powerful thermals (rising masses of hot air) to keep them aloft.

As far as the shape of their wings is concerned, ravens have pointed wings with long primary feathers near their tip. Crows, meanwhile, have blunter wingtips; although their primaries are splayed as well, they are shorter and less pronounced than a raven’s.

Perhaps the single most distinctive difference between the two is the shape of their tails. All the feathers in a crow’s tail are the same length; in flight, their extended tails look like fans, with a rounded outline. Ravens meanwhile have longer feathers in the middle of their tails, giving them a wedge-like outline while the birds are in flight.

The differences between these two species are subtle — as well they should be, they are closely related, after all! The Corvidae family is also very numerous, and each species that belongs to it has its own particularities, some of which may not fit with what we’ve discussed here today. In general, however, they’re distinctive enough to tell apart.

Crows and ravens are some of the most similar — and most often-confused — species in this family. Hopefully the tips here will help you better tell them apart, and impress your friends with your knowledge of Corvidae!

Migratory birds have lighter feathers to deal with the heat

Flying nonstop for hundreds of kilometers can be a difficult task for migratory birds. To go through it, birds developed many adaptations — some of which we’re only now starting to understand. In a new study, researchers found that on average, migratory birds are lighter colored than species that don’t migrate, which helps them reduce the amount of heat absorbed from the sun during the trip.

Image credit: The researchers.

Migratory birds undertake long and extremely challenging journeys, which puts great pressure on their entire bodies — from the sensory mechanisms that facilitate orientation to physically enduring the whole thing. It’s not just the distance, or finding food and water, or staying on track — there’s plenty of other, less-obvious challenges as well. For instance, sunlight. With birds sometimes flying at higher altitudes, sunlight can become a major problem, overheating them and potentially causing great problems.

Studies have suggested that birds increase their flight altitude dramatically during the day compared to at night to cope with radiation. It has also been hypothesized that animals benefit from being darker when living in cold regions and from being lighter where it’s warm because lighter colors absorb less solar radiation. If lighter-colored plumage keeps birds cooler, then migratory species should be lighter colored than residents, a group of researchers at the Max Planck Institute suggested.

“Flying at higher altitudes where it is colder may offset the heat generated by absorbing solar radiation. Thus, we wondered whether an alternative response to reduce the risk of overheating while migrating in the sun would be for migratory species to evolve lighter plumage colors,” Kaspar Delhey, study author, told ZME Science.

Understanding migratory birds

To check whether this was the case, Delhey and colleagues quantified the overall plumage lightness of all bird species, assigning a score of 0 for birds that are completely black to 100 for being completely white. They used bird images from the Handbook of the Birds of the World, a multi-volume set of books that summarizes what is known for all bird species we know of – which is now online and can be seen here.

The researchers extracted the image of the bird from the background using machine learning and averaged the color for all pixels in the image. This took quite a bit of trial and error and a lot of computational power, Delhey explained. But after a while, they were able to compare the data on coloration with species migratory behavior, while controlling other factors that affect plumage color. 

The findings showed that birds get lighter as they migrate more, which also means resident species are darker than those who migrate. The pattern was consistent across different types of birds, either small, large, waterbirds, and land-dwelling birds. It’s a reminder of the role climate factors play in the evolution of animal coloration, the researchers said. 

Looking ahead, the team wants to continue exploring the dataset to further examine whether and how migratory behavior and other variables (such as habitat use and size) affect the evolution of aspects of color variation other than light to dark variation. They are especially interested in finding factors that predict the type of color.

“In addition, we expect that in the next years the importance of thermoregulation in migratory birds will be directly studied taking advantage of recent technological advances. For example, now it is possible to measure the temperature of birds while they migrate at the same time as their flight altitude, speed and heart rate,” said Delhey. 

The study was published in the journal Current Biology. 

Bird populations in Europe plummeting since the 1980s

One in six birds in Europe has disappeared, according to a survey that compared today’s bird populations in Europe to those in the 1980s. Overall, the continent lost about 600 million birds.

The house sparrow is one of the most affected birds. Image credit: Flickr: Pete Beard.

While not as known as climate change, biodiversity is also facing a deep crisis, with researchers repeatedly emphasizing that we’re causing a sixth mass extinction. A previous study by the World Wildlife Fund (WWF), called the Living Planet Report, found that the population sizes of birds, fish, mammals, and amphibians have declined a whopping 68% since 1970. 

In a new study, researchers from Birdlife International, the Czech Society for Ornithology and the Royal Society of the Protection of Birds brought together two large datasets to explore abundance change in Europe’s birds. Integrating the two allowed to double the number of species included and to extend the temporal range.

The group of researchers analyzed data for 378 out of 445 native bird species in European Union countries and estimated a decline between 17% and 19% between 1980 and 2017. 

“This report loudly and clearly shows that nature is sounding the alarm. While protecting birds that are already rare or endangered has resulted in some successful recoveries, this doesn’t seem to be enough to sustain the populations of abundant species, Anna Staneva, BirdLife Europe Interim Head of Conservation, said in a statement.

Heavy declines

The house sparrow (Passer domesticus), which used to be very common all over the continent was the worst hit, the study found, losing 50% of its population since 1980 — a total loss of 247 million birds. Meanwhile, its close relative, the tree sparrow (Passer montanus), has declined by 30 million individuals. Both species were affected by changes in agricultural policy and management. 

In fact, the most significant change was registered in farmland and grassland birds. Farming practices have been widely thought to cause a decline in wildlife, and this study clearly showcases just how big of an impact these changes can have on wildlife. Damaging practices include the growing use of monocultures and pesticides, changes in grassland management, field drainage, and overall larger field sizes. 

Most of the observed decline in bird numbers happened during the 1980s and the 1990s, with the decline rate slowing down (but not stopping) in the last decade. The authors linked this to recent regulations implemented in the EU that give legal protection to priority species and also extend their protected habitats, such as the Birds and the Habitats Directives. 

In fact, seven species of birds of prey increased in recent decades thanks to more comprehensive protection, new targeted recovery projects, and limited use of pesticides, the study showed. If the EU hadn’t implemented the directives on birds protection, declines in many bird species would have been much worse, the authors wrote.

“Our study is a wake-up call to the very real threat of extinctions and of a Silent Spring, and we are fully supportive of ensuring a strong framework which puts conservation front and centre of any global plans” Fiona Burns, RSPB scientist, said in a statement. “We need transformative action across society to tackle the nature and climate crises together.”

The researchers also highlighted the upcoming UN conference next year to negotiate a new global agreement on biodiversity conservation, after the previous one failed to deliver most of the targets. The upcoming agreement should increase conservation efforts to prevent further declines in the number of birds worldwide, the researchers wrote.  

The study was published in the journal Ecology and Evolution.

One in five bird species in Europe is threatened by extinction

Because of how sensitive they are to changes in their environment, birds are a perfect indicator for gauging biodiversity. If they are in danger, we all likely are. In Europe, one out of five bird species is currently threatened by extinction, while one out of three has declined over the last few decades, according to BirdLife International.

Image credit: Flickr / Koshy Koshy.

The NGO released the European Red List of Birds, a review of the regional extinction of all 544 species of birds found in over 50 countries in Europe. Species are evaluated from “least concerning” to “extinct” based on data collected by thousands of experts and volunteers. It’s the fourth assessment, following editions in 1994, 2004 and 2015. 

“Birds have been on this planet for longer than we have, but at the speed humans are exploiting and destructing, we are seeing some species plummet towards extinction. The Red List is a crucial resource for everyone working to stop the biodiversity and climate crises,” Anna Staneva, Interim Head of Conservation at BirdLife Europe, said in a statement. 

A growing crisis

At the European regional level, 13% (71 species) of bird species are threatened, with approximately 2% (8 species) Critically Endangered, nearly 3% (15 species) Endangered, and nearly 9% (48 species) Vulnerable. A further 6% (34 species) are considered Near Threatened, while five species are considered Regionally Extinct. 

Changes between categories since the previous assessment in 2015 were recorded for 84 species, of which 37 species were classified in a higher extinction risk category and 47 in a lower category. Most of these changes are due to deterioration or improvement in the species populations, while a smaller part is because of methodological changes.

The report showed that waders, raptors, seabirds and wildfowl have the highest share of threatened and near threatened species per taxonomic group, along along with smaller groups such as kingfishers, bustards and grebes. Over 40% of wildfowl and wader species, as well as over 30% of seabirds and 25% of raptors are experiencing population declines. 

The main drivers of declining bird populations observed in European habitats include large-scale land-use change, intensive agricultural practices, over-exploitation of marine resources, pollution of inland waters, unsustainable forest practices and infrastructure development.

Examples include the Common Snipe (Gallinago gallinago), facing habitat loss due to agriculture, the Black-necked Grebe (Podiceps nigricollis), affected by water pollution from urban run-offs, the Great Spotted Woodpecker (Dendrocopos major), challenged by forestry, and the Turtle Dove (Streptopelia turtur), challenged by powerful pesticides.

“Bird populations in Europe are dropping mainly because they are losing their habitats, and there are solutions to that. Large-scale restoration work alongside the protection of the few natural habitats left in Europe, will not only help birds survive, but will help humanity survive,” Claire Rutherford, Species Conservation Officer at BirdLife Europe, said in a statement. 

Still, it’s not all bad news this year. The Red Kite (Milvus milvus) and the Azores Bullfinch (Pyrrhula murina) are two recently successful conservation stories, which shows targeted approaches to species can work. There were also good examples of agri-environment schemes that can help declining species, such as the Corncrake (Crex crex).

The full report can be read here. 

Raptor birds around the world are in decline, as they struggle with habitat loss and poisoned foods

Birds of prey are declining all throughout the world, according to new research, putting the health of ecosystems at risk. Habitat destruction is the main driver of this decline.

Image via Pixabay.

The paper analyzed data from the International Union for the Conservation of Nature (IUCN) and BirdLife International, a global partnership of non-governmental organizations involved in the conservation of birds and their habitat. Overall, the data showed that around 50% of the 577 bird of prey (raptor) species worldwide are declining in number. Roughly 30% are threatened, vulnerable, endangered, or critically endangered, with 18 species falling into the latter category.

Several species are also at risk of becoming locally extinct, even if they’re faring relatively okay as a whole species, the team explains. This means that they would no longer be able to act as top predators in certain ecosystems, a role critical for ecosystem health.

Bird issues

“The golden eagle is the national bird of Mexico, but we have very few golden eagles left in Mexico,” said Gerardo Ceballos, a bird scientist at the National Autonomous University of Mexico and co-author of the study.

The main threat to these birds is habitat destruction, the team explains, both through the direct issues it creates for them, such as a lack of adequate nesting areas, increased in-species competition for space and resources, as well as through indirect effects, including lower populations of animals that serve as prey.

Over half of raptor birds that are most active during the day (54%), including most hawks, eagles, and vultures, are showing ongoing population declines. Nocturnal raptors are faring somewhat better, with only 47% of species in this category showing population decline. This showcases that birds are experiencing strong pressures right now, not past pressures that have affected their numbers but have been addressed in the meantime. In other words, affected species will only fare worse over time, and it’s possible that new ones will also start being affected unless action is taken.

Apart from habitat destruction, other leading causes for the decline of raptors highlighted in the study include compounds such as rodent poison, used in agriculture, and lead shot that is typically used for hunting birds. Raptors routinely feed on rodents and carrion, so these compounds inadvertently affect them. Heavy use of anti-inflammatory drugs in livestock is also propelling the rapid decline of raptors, through the same mechanism. This is an issue particularly in South Asia, where some species have declined by 95% in recent decades due to the consumption of livestock carcasses.

The paper lists 4,200 sites previously identified by conservation groups as being essential for the health of raptors globally. According to the team, most of these are not protected in any way, or only enjoy partial coverage by protected areas. To illustrate how this state of affairs can impact raptor communities over a wide geographical range, the authors give East Asia as an example. Raptor species here tend to breed in north China, Mongolia, or Russia, and then migrate down the eastern coast of China to spend summers in Southeast Asia or India.

Multiple species will thus travel through a handful of sites throughout their migrations, so issues in any one of them will have wide-ranging impacts. Eastern China, for example, is very densely populated and highly urbanized, so sites in this area are facing massive pressures from human activity, including habitat destruction and contamination with agricultural compounds.

The paper “Global patterns of raptor distribution and protected areas optimal selection to reduce the extinction crises” has been published in the journal PNAS.

Humans have driven hundreds of bird species to extinction in the last 50,000 years

Birds are apparently going through a major extinction event. According to a new study, humans have caused the extinction of up to 20% of the entire avian species diversity over the last 50,000 years.

Image credit: Flickr / Mathias Appel.

There are hardly any habitats on Earth that have not been affected by humans yet. As we modify and reshape the land around us, we also damage or even destroy natural habitat that is crucial for birds. The habitats we create instead, such as farms and cities, are more often than not poor substitutes for the habitats they supplant, supporting a lower diversity of bird species.

At the same time, climate change is now also a problem, as it threatens to exacerbate the damage from habitat loss, creating new challenges that birds must overcome. This includes changing habitat distributions and a shift in the timing of food supplies that birds rely on — which, especially for migratory birds, is a big problem.

In a new study, researchers from Tel Aviv University aimed to quantify the known avian extinctions and assess the relevance of the factors thought to have promoted their extinctions. Few attempts were made in the past to determine how many extinctions are actually known. Most extinct species shared several features: they were large, lived on islands, and were flightless.

“We conducted a comprehensive review of scientific literature, and for the first time collected quantitative data on the numbers and traits of extinct species of birds worldwide. Those that became extinct in the last 300 years or so are relatively well known, while earlier species are known to science from remains,” Shai Meiri, co-author of the study, said in a statement.

Looking at birds extinction

The researchers recorded the geographic range, flight ability, and body size of each bird species. If mass data were unavailable, they estimated them from linear measurements. Then they modeled masses of extinct birds on those of extant ones and estimated the effects of taxonomy, body mass, insularity, and flight ability.

Altogether, they were able to list 469 avian species that became extinct over the last 50,000 years, but they believe that the real number is actually much higher. The extinction was caused primarily by humans, who hunted the birds for food, or by animals brought to islands by humans, that then fed on the birds or their eggs.

The assumption is based on the fact that a greater part of bird remains was found on human sites, apparently belonging to birds consumed by the inhabitants. Also, in most cases, the extinctions occurred a short time after the arrival of humans. Extinction wasn’t random, as most extinct species shared a set of common features, the study showed. In other words, everything points to *something* killing the birds — humans.

About 90% of the extinct birds lived on islands. When humans arrived there, the birds were hunted by them, or fell victim to other animals introduced by humans. Most birds were large or very large and provided a great quantity of food. In fact, the body mass of the extinct species was found to be up to 10 times as large as that of the surviving species. 

A large portion of the bird species was flightless and couldn’t escape their pursuers. The number of flightless bird species that became extinct is double the number of flightless species still existing today, the study showed. Overall, 68% of flightless bird species known to science became extinct. A well-known example is the moa bird (dinornitiformes).

“Before the major extinction event of the past millennia, many more large, even giant, as well as flightless avian lived on our globe, and the diversity of birds living on islands was much greater than today. We hope that our findings can serve as warning signals regarding bird species currently threatened with extinction,” Meiri said in a statement. 

The study was published in the journal Biogeography. 

Feed the birds without worrying, new study says — they won’t get addicted to your food

Bird feeders out there, rejoice! The small songbirds that visit the feeders in your yards are unlikely to develop an unhealthy reliance on them. In a new study, researchers looked at the feeder use habits of black-capped chickadees (Poecile atricapillus) and found nothing to suggest such a reliance — which was becoming a concern among feeders around the world.

Image credit: The researchers.

Intentional feeding of wildlife by humans is a widespread activity that occurs throughout the world and supports a multi-billion-dollar global industry. For example, more than 50 million people in the United States provide supplemental food for birds, with more than US$4 billion spent annually on bird food, feeders, and accessories.

However, the extensive and widespread nature of intentional feeding has a range of consequences for wild, free-ranging animal populations, which are best documented in birds. These include negative effects such as facilitating disease transmission, enhancing competition and impairing breeding performance, and restructuring local communities.

As more is learned about how wild bird populations are impacted, discussion around whether such practices should be regulated has led some countries to establish policies and best management practices regarding supplemental feeding of wildlife. This is especially relevant for northern latitudes, where bird feeding is more common.

Nevertheless, very few studies have actually evaluated whether free-ranging birds increase their reliance upon supplemental food sources during demanding periods such as winter — so the debate on whether or not birdfeeders produce an unhealthy reliance is still done in the blind. Or rather, it was until now.

“There’s still much we don’t know about how intentional feeding might induce changes in wild bird populations, but our study suggests that putting out food for small birds in winter will not lead to an increased dependence on human-provided food,” Jim Rivers, an animal ecologist at Oregon State University and co-author, said in a statement. 

The researchers studied the feeder use habits of black-capped chickadees subjected to one of these flight-feather-clipping treatments: heavy clipping, light clipping or, as the control, no clipping. Experimental removal of primary flight feathers is an established technique for altering wing loading and increasing the energy costs of flight.

The chickadee was specifically chosen because of its small size and the fact that frequents feeders during winter throughout its range. It has high daily energy requirements and typically takes one seed at each feeder visit, allowing for a clear measure of feeder visitation rate. The birds were tagged with chips, and 21 feeders were filled with sunflower seeds. 

The study found that the experimentally handicapped chickadees, those experiencing elevated flight costs, didn’t increase their rates of visitation to the feeders. Instead, feather-clipped birds actually decreased their feeder use for a couple of weeks, probably due to less exposure to predation, but then used the feeders at levels similar to the unclipped control birds. 

“Feather-clipped chickadees reducing their use of feeders relative to control birds suggests that foods in the environment were sufficiently available to compensate for increased flight costs and allowed them to cut back on feeder use,” Rivers said. “It’s clear that the chickadees in our study didn’t increase their visitation rates nor did they increase their reliance on supplemental feed.”

The study was published in the Journal of Avian Biology. 

Scientists may have found how migrating birds sense Earth’s magnetic field

Birds migrate thousands of miles without a GPS, using the Earth’s magnetic field to orient themselves. It’s been a long mystery how they were able to do this, but now, scientists may have found the key reason behind it: a molecule in the eye that’s sensitive to magnetism and gives birds a working internal compass. 

Image credit: Flickr / Piplongstockings

Quantum birds

A group of biologists, chemists, and physicists tested a 40-years old theory according to which a light-sensitive molecule interacts with the Earth’s magnetic field via a quantum chemical process. To do this, they looked at a light-sensitive protein called cryptochrome 4 (CRY4) from the retina of European robins (Erithacus rubecula).

“We think we may have identified the molecule that allows small migratory songbirds to detect the direction of the Earth’s magnetic field, which they undoubtedly can do, and use that information to help them navigate when they migrate thousands of kilometres,” Peter Hore, researcher and co-author of the paper, told BBC News.

European robins live throughout Europe, Russia and western Siberia. Some migrate south every northern hemisphere winter, for example from Scandinavia to the United Kingdom, and return in spring. Many migrating robins are faithful to both their summer and winter territories, which may be many hundreds of kilometers apart.

Previous studies have shown that certain species of birds use Earth’s magnetic fields when they migrate. Suspicion had fallen on the CRY4, a light-sensitive protein, and the first one identified in animals that evolved specifically to detect magnetic fields. It’s part of a class of proteins known as cryptochromes, involved in the workings of circadian rhythms.  

Now, researchers managed to isolate the molecule from robins and showed that it is sensitive to magnetic fields. In the presence of light, electrons can jump between different parts of CRY4 and between it and another molecule called flavin adenine dinucleotide (FAD), ultimately leading to the production of a compound called CRY4-FADH. 

Changes in the level of the compound may allow light-sensitive cells in the eye to alter their output, making the view lighter or darker, depending on the direction and strength of the magnetic field in the bird’s field of vision, Henrik Mouritsen, co-author, told New Scientist. “You may be able to see where north is as kind of a shading on whatever else you would be seeing,” he said. 

For comparison, the researchers also looked at CRY4 proteins from chickens and pigeons, which are not migratory birds, but do contain this light-sensitive protein. Each species has a slightly different version of the molecule, and the team found that these two are less affected by magnetism. This suggests that the version of the molecule in migratory birds has been fine-tuned to amplify its sensitivity.

While the findings are exciting, the study hasn’t demonstrated that CRY4 is being used for magnetic sensing in real life. The researchers only looked at this molecule in isolation. Nevertheless, the fact that the molecule is more magnetically-sensitive in robins than in birds such as chickens that don’t migrate makes them optimistic about their findings. 

The study was published in the journal Nature. 

How many birds are there in the world? AI estimates around 50 billion

The house sparrow might be small, but with 1.6 million of them, they’re by far the most populous bird in the world. Credit: Corey T. Callaghan.

Through a combination of citizen science and big data analytics, researchers have estimated the entire global population of birds. There are roughly 50 billion individual birds chirping and flapping across the world, about six birds for every human.

“Humans have spent a great deal of effort counting the members of our own species – all 7.8 billion of us,” says Associate Professor Will Cornwell, an ecologist at the University of New South Wales and co-senior author of the study.

“This is the first comprehensive effort to count a suite of other species.”

In order to estimate the number of birds in the whole world, the researchers in Australia pooled together almost a billion bird sightings from eBird, an online database of bird observations curated by citizen scientists and run by the Cornell Lab of Ornithology. Over 600,000 people contributed information to the database. This data included the species of bird, the location of the sighting, the size and color of the individual, whether or not it was close to a city, and other factors that were used to calculate a species’ ‘detectability’ — a measure of how likely it is for a person to spot a particular bird.

There are over 9,700 different bird species that we know of, and the eBird catalog covers 92% of these species. The remaining 8% of species are very rare species that are rarely sighted, meaning their numbers are very low so their exclusion from the analysis shouldn’t have much impact on the overall estimate.

While some species are threatened with extinction others are incredibly abundant. In fact, four bird species are in what researchers call ‘the billionaire club’, due to having an estimated population of over a billion. These include the house sparrow (1.6 billion), followed by the European starling (1.3 billion), ring-billed gull (1.2 billion), and barn swallow (1.1 billion).

But while a select few of ‘one percenters’ dominate the ecosystems, many others are struggling to survive. Around 12% of bird species included in the study have an estimated population numbering less than 5,000, making them extremely vulnerable to extinction. These include birds such as the Chinese Crested Tern, Noisy Scrub-bird, and Invisible Rail.

The researchers plan on doing a follow-up study a decade from now to see how the most vulnerable species fare in the meantime. If these populations fare worse, it could be a real alarm bell for the health of their native ecosystems.

Naturally, this assessment isn’t definitive since it relies on extrapolating sightings. Some of these sightings may be inaccurate, but at least some degree of uncertainty is to be expected when working with very large, global datasets such as eBird.

“While this study focuses on birds, our large-scale data integration approach could act as a blueprint for calculating species-specific abundances for other groups of animals,” says study lead author Dr. Corey Callaghan, who completed the research while he was a postdoctoral researcher at UNSW Science.

“Quantifying the abundance of a species is a crucial first step in conservation. By properly counting what’s out there, we learn what species might be vulnerable and can track how these patterns change over time – in other words, we can better understand our baselines.”

The researchers would like to invite any birdwatching enthusiast to contribute to eBird. As more data becomes available, the researchers plan to perform more robust analyses that may paint a more accurate picture of the state of bird ecosystems across the globe. Ultimately, this information will greatly inform conservation efforts to direct resources where they’re the most needed.

“A great starting point is to learn a handful of birds that come to your local area, like Rainbow Lorikeets, Sulphur Crested Cockatoo, and Australian White Ibis,” Cornwell says.

“It can be as simple as seeing if you can spot any out the window while you’re drinking your coffee in the morning.”

The findings appeared in the Proceedings of the National Academy of Sciences.

This is the world’s most “instagrammable bird” — and you’d never guess it

If you had to pick the most “instagrammable bird” in the world, you probably wouldn’t go for the frogmouth (Podargus strigoides) — a nocturnal bird found in Australia and Southeast Asia that is often mistaken for an owl.

But science says otherwise. A study analyzed almost 27,000 photos of birds across Instagram accounts with a combined following of 3.5 million users and found the unassuming frogmouth took the top spot in the ranking.

The Frogmouth. Image credit: Flickr / Rae Allen

“It just does not look like any other bird, with its almost anthropomorphic facial features,” lead researcher Katja Thommes, a psychologist from the University of Konstanz in Germany, told BBC. “And frogmouths are quite rare. Even in our 20,000-image database, it featured only 65 times.”

Thommes and a group of German researchers were curious to see what makes a great bird photo. They found that despite popular belief, appeal has little to do with conventional notions of beauty. We might “like” a photo over a bird’s color or some specific appealing feature, but oftentimes, the more unusual an animal looks, the more people respond to it — and the more interest it draws.

To see which bird would likely raise the most interest on Instagram, the researchers used a method called Image Aesthetic Appeal (IAA), which is based on the liking behavior in Instagram. In a nutshell, the method computes a measure of aesthetic appeal based on the number of likes. The score normalizes absolute numbers of likes for time and reach, that is, for how many people have presumably seen an image.

“I thought this method, the I.A.A. score, will be a great tool to investigate bird photographs in terms of aesthetic appeal and inform people which birds are the most photogenic,” Gregor Hayn-Leichsenring, the study’s co-author, told The Guardian. “Or possibly, I just wondered why nobody likes my own bird photographs.”

The turaco, one of the birds that was on top of the ranking. Image credit: Flickr / Charles Ewing

Instagram is home to numerous bird-focused accounts, and the platform hosts a constant stream of bird photographs with several hundred thousand followers. For the study, the researchers picked nine of the largest bird accounts and collected a total of 27,621 images, calculating IAA scores for each of them and extracting the species of each bird.

The surprising winner in the ranking was the frogmouth, which the researchers see as poetic justice, considering it was once named the world’s “most unfortunate-looking bird.” Well, there is some karma in the world.

These stocky and disheveled birds have piercing yellow eyes and wide, hooked beak, which gives them their name.

“They look perpetually angry,” Tim Snyder, the curator of birds at the Brookfield Zoo in Chicago, told the New York Times. “The look on their face just looks like they’re always frustrated or angry with you when they’re looking at you, and that’s just the makeup of the feathers and the way their eyes look and everything. It’s kind of funny.”

The magpie is a common bird that ranked surprisingly high on the list. Image credit: WIkipedia Commons

Other birds high up in the ranking are colorful pigeons with decorative plumage, the emerald turaco (Musophagiformes) with its crown-like head feathers, and the hoopoe also wearing a distinct feather crown and showing off typical high-contrast feathering. Magpies (Corvidae) and broadbills (Myiagra) also ranked high on the Instagram list.

On the low end, the researchers found two types of seabirds, the sandpipes (Scolopacidae) and the oystercatcher (Haematopodidae). Storks (Ciconiiformes) and vultures (Falconiformes) also complete the team of the not-so-appreciated birds. You can read the full list here.

The sandpipe. Image credit: Wikipedia Commons

“The ranking of bird families demonstrates that the IAA score is not necessarily tied to the beauty of the depicted bird. Presumably, interestingness, idiosyncrasy, and the situational context all play their part in the aesthetic appeal of bird photos to the human observer,” the researchers wrote.

While the study didn’t focus on this, perception matters for conservation purposes. Simply put, more popular animals get the attention, while less popular ones are left behind. By analyzing which animals are more popular, researchers can make sure they also receive the much-needed conservation attention.

The study was published in the journal i-Perception.

France becomes last EU country to ban hunters from gluing birds to trees

Considered by many to be unnecessarily cruel and harmful to the environment, the hunting technique of coating branches with glue to trap songbirds will soon come to an end to France, the only European country in which such practices were still allowed.

Image credit: Flickr / Sue

It wasn’t easy to convince the French government to take action against glue trapping. France only agreed to put a stop to the practice following pressure from conservationists, a formal ruling by the European Court of Justice (ECJ), and a threat by the European Union’s executive body to start legal action against the country. The suspension, issued by President Emmanuel Macron, will enter into force from the upcoming hunting season.

Until recently, the French government had found a way around it by allowing the hunting technique only in five departments in south-east France on the grounds that it was “controlled, selective and in limited quantities”. Supporters of the hunting method argued that rapping birds on glue-covered twigs is a cultural tradition. But for the ECJ this wasn’t the case, ruling this week that the practice contravened EU rules.

“It’s wonderful news. Now France cannot use the pretext of an opt-out to allow glue-trapping to happen,” Yves Verilhac, of France’s Bird Protection League (LPO), told The Guardian, celebrating the news. “The judgment is very interesting because it says that tradition is no excuse for this and that it is absolutely not selective, which is what we knew and argued.”

The excitement wasn’t shared by the hunters. In a television interview on Thursday Willy Schraen, the head of the hunters’ federation, called the suspension “unacceptable” and said the hunters should be left alone by the government. “Why is this an issue to occupy Europe and our minister?” he added.

There are about 1.5 million registered hunters in France and they represent an important voting bloc in rural areas. President Macron has made efforts to attract their support since he was elected in 2017, which partly explains why France remained as the single country in the EU not to ban the technique – used by 5,000 hunters in the country, according to the hunter’s federation.

The glue-covered bird traps are used to catch songbirds like thrushes (Turdidae) and blackbirds (Turdus merula). Conservationists argue they traps are cruel to the trapped songbirds and threaten endangered species, as they trap many kinds of birds. The EU outlawed glue traps in 1979 but France remained until know as the single country to not accept the block’s rules.

French hunters kill an estimated 17 million birds a year from 64 species, more than any other European country, according to LPO. Of the bird species, 20 are listed as endangered by the International Union for Conservation of Nature (IUCN), including the turtle dove (Streptopelia turtur), rock ptarmigan (Lagopus muta), redwing (Turdus iliacus), and curlew (Numenius)

The industrial glue used in the traps can be toxic for birds, while the solvents used to detach the animals can harm trees and soil. It’s also needlessly cruel, as campaigns to ban the hunting technique have shown multiple times over the years, releasing footage of how birds suffer as they are trapped. Their next step will be asking the government to ban other practices, like trapping birds with nests.

The Clean Air Act in the US saved 1.5 billion bird lives over the past 4 decades

Pollution regulations in the U.S. are helping people and birds both, a new study reports. The findings showcase how federal measures meant to reduce ozone pollution likely prevented around 1.5 billion bird deaths over the past 40 years, roughly one-fifth of the US’ current bird population.

Image via Pixabay.

Keeping our environment clean and tidy benefits everybody quite literally. The effects of pollution on public health have been investigated in the past, but it also affects wildlife. The current study comes to flesh out our understanding of its effects on the general health of bird species.

In this together

“Our research shows that the benefits of environmental regulation have likely been underestimated,” says Ivan Rudik, a lead author and Ruth and William Morgan Assistant Professor at Cornell’s Dyson School of Applied Economics and Management.

“Reducing pollution has positive impacts in unexpected places and provides an additional policy lever for conservation efforts.”

The study was conducted by scientists at Cornell University and the University of Oregon. They based their research on a series of models from the Cornell Lab of Ornithology’s eBird program, which they ran alongside ground-level pollution data, to track monthly changes in bird abundance, air quality, and regulation status for 3,214 U.S. counties over a span of 15 years.

The researchers then analyzed how these trends were impacted by the NOx (nitrogen oxide) Budget Trading Program, an initiative of the U.S. Environmental Protection Agency meant to limit summertime ozone emissions from large industrial sources.

Ozone is a gas that occurs in nature and is also produced by human activities, including by power plants and cars. It can be good or bad. A layer of ozone in the upper atmosphere protects the Earth from the harmful ultraviolet rays of the sun. But ground-level ozone is hazardous and is the main pollutant in smog. 

The results show that ozone pollution is most damaging to small migratory birds including sparrows, warblers, and finches; these make up around 86% of all land bird species in North America, the team explains. Ozone damages these animals’ respiratory tracts and harms their food sources.

“Not only can ozone cause direct physical damage to birds, but it also can compromise plant health and reduce numbers of the insects that birds consume,” explains study author Amanda Rodewald, Garvin Professor at the Cornell Department of Natural Resources and the Environment and Director of the Center for Avian Population Studies at the Cornell Lab of Ornithology.

“Not surprisingly, birds that cannot access high-quality habitat or food resources are less likely to survive or reproduce successfully. The good news here is that environmental policies intended to protect human health return important benefits for birds too.”

Previous research has found that bird populations in North America have shrunk by roughly 3 billion individuals since 1970. However, without regulations such as the Clean Air Act, the team estimates that we could have seen some 1.5 billion more bird deaths over the same timeline. The study brings forth the “first large-scale evidence” that ozone pollution can lead to wildlife mortality, and that measures implemented to protect humans from air pollution can also bring significant benefits to birds.

“Regulations intended to save human lives also bring significant conservation benefits to birds,” says Catherine Kling, Tisch University Professor at the Cornell Dyson School of Applied Economics and Management and Faculty Director at Cornell’s Atkinson Center for Sustainability. “This work contributes to our ever increasing understanding of the connectedness of environmental health and human health.”

The paper “Conservation Co-Benefits from Air Pollution Regulation: Evidence from Birds” has been published in the journal The Proceedings of the National Academy of Sciences.

Urban seagulls know exactly when to strike to steal your food — we have the GPS data to prove it

Seagulls have become a common (and often unwanted) sight in urban areas. The birds are increasingly moving to cities for the abundant food, up to the point where chip-eating seagulls bothering city dwellers has become a fairly common occurrence. According to a new study, seagulls are even adapting their schedule to better forage off humans.

Seagulls. Waiting, watching, plotting their next attack. Image credits: Karim Manjra

Cities are unusual habitats. Unlike natural environments, where the interspecies relationships have been chiseled and honed over many generations, cities are noisy, polluted, and weird, built from unwelcoming materials. For most creatures cities are a disaster, completely wrecking any chance of a real habitat. But for a minority of creatures, cities are a godsend.

Just think about rats, seagulls, and roaches — a trio that seems to inhabit every big city on the planet. These creatures (and several others) have not only adapted to urban areas, but they’re often thriving in them. A big part of this adaptation is knowing how to shift their lifestyle based on fluctuations in food sources. Researchers suspected some sort of adaptation must be taking place, but until recently the data had been scarce.

To address this, a team of scientists at Bristol’s Faculties of Engineering and Life Sciences equipped 12 lesser black‐backed seagulls with mini GPS tracker backpacks, recording their behavior at three different settings: a public park, a school, and a waste center. The team also used other observations of gulls at a various number of different sites.

The team found that birds move their foraging patters to closely match the timing of school breaks and the opening and closing times of the waste centre. In other words, they’re not foraging when they’re the hungriest: they’re foraging when they know they have the best chance to find something. Their activity in the park also seemed to correspond with the availability of food sources in the park, but this was not connected to human activity.

Feeling cute, might steal some food later. Image credits: Spelt et al.

This suggests that the birds have the capacity to adapt their foraging patterns and the intelligence to do so, says Dr. Anouk Spelt, lead author of the paper published in Ibis, the International Journal of Avian Science.

“Our first day at the school, the students were excited to tell us about the gulls visiting their school at lunch time. Indeed, our data showed that gulls were not only present in high numbers during lunch time to feed on leftovers, but also just before the start of the school and during the first break when students had their snack. Similarly, at the waste centre the gulls were present in higher numbers on weekdays when the centre was open and trucks were unloading food waste.”

There’s also some good news: seagulls aren’t really planning to steal your chips, they’re more interested in other types of food readily available in parks.

“Although everybody has experienced or seen gulls stealing food from people in parks, our gulls mainly went to park first thing in the morning and this may be because earthworms and insects are present in higher numbers during these early hours,” says Spelt.

It’s also interesting that the number of gulls and the number of people at the school were positively related only during weekdays — during weekends, the relationship was opposite. So humans can both attract and deter seagulls, based on the birds’ perception. A weekday behavior was also observed at the waste center where during working days, waste was unloaded regularly (up to 15 times a day) during the opening times. At the weekend, however, no new waste was unloaded due to the center being closed, and birds were less likely to come to the center. At both locations, the gulls were observed waiting on the surrounding rooftops before school breaks and before waste was unloaded, implying that they were waiting there specifically for food to become available.

The behavioral flexibility of the gulls also impresses co-author Dr. Shane Windsor, who concludes:

“With this study in Bristol we have shown that gulls in cities are able to adapt their foraging schedule to make best use of food resources depending on their availability. Some gulls even used all three feeding grounds in the same day, suggesting they might track the availability to optimise their energy intake. These results highlight the behavioural flexibility of gulls and their ability to adapt to the artificial environments and time schedules of urban living.”

Journal Reference: Spelt et al. Urban gulls adapt foraging schedule to human‐activity patterns. https://doi.org/10.1111/ibi.12892

Want to help endangered birds? This music album could be the place to start

An international group of electronic musicians and composers is sampling the sounds of endangered birds as a way to save these lyrical creatures and raise awareness about the challenges these birds are facing.

The artists just published a new album in which they combine their own beats with the sounds of the birds, donating all the profits to conservation efforts.

The cover of the new album

“A Guide to Birdsong” was started in 2015 by Robin Perkins, a 33-year old composer, DJ, and producer from England. He wanted to take “the songs of endangered birds and challenging musicians to make a piece of music from them,” trying to “marry the worlds of activism of conservation, birdsong and electronic music,” he said.

Perkins worked with a group of artists from each of the endangered or threatened birds’ homelands to build their own songs around the birds’ songs. Electronic music allows artists to do that in a special way, he said.

The first album was focused on South America and raised more than $15,000 for two bird conservation charities.

“The beautiful thing about electronic music is that it opens up this whole toolbox of things that you couldn’t otherwise do, right?” Perkins said in a statement. “So you can take a sample of a bird song and do 5 million things to it. You can turn it into an instrument itself. You can reverse it, you can add effects, you can sample it.”

Following the initial success, Perkins just published a second album featuring birds from Mexico, Central America, and the Caribbean. He invited musicians from around the region, asking for the tracks to include a birdsong from a bird in the range of “near threatened” to “critically endangered.” The 10-track album includes sounds of a wide array of creatures, including the black catbird, bearded screech owl, and the thick-billed parrot. The tracks were done by diverse artists like Garifuna Collective from Belize, Di Laif from Guatemala, Tamara Montenegro from Nicaragua, and many more.

Montenegro chose Nicaragua’s national bird, the turquoise-browed motmot, also known as Guardabarranco. The bird is threatened by loss of habitat primarily due to deforestation. “As a child, I would see this bird freely flying around and meeting his partner in my backyard for sunsets,” she said in a statement, explaining her choice.

The profits collected from the new album will go towards three initiatives that are focused on birds and the conservation of them in Central America and the Caribbean. This includes educating young people about birds, building aviaries to help ones that are injured, promoting birding, and training local guides.

Lisa Sorensen, head of Birds Caribbean, one of the organizations set to benefit from the sales of the album, said in a statement: “We’re envisioning that funding from this project will help us advance on building the supply and the demand for sustainable bird and nature tourism.”

Florida’s birds of prey are full of microplastics

A new study from the University of Central Florida (UCF) has found, for the first time, microplastics in terrestrial and aquatic birds of prey in the state.

Image credits Harry Burgess.

Some of the birds in whose digestive systems the team found microplastics include hawks, ospreys, and owls. The accumulation of such material can lead to starvation and poisoning, either of which can be life-threatening. The findings are particularly worrying because birds of prey are critical to a functioning ecosystem, the authors note.

A bird’s gut view

“Birds of prey are top predators in the ecosystem and by changing the population or health status of the top predator, it completely alters all of the animals, organisms and habitats below them on the food web,” says Julia Carlin, the study’s lead author and a graduate of UCF’s Department of Biology.

Microplastics are pieces of plastic that are under 5 mm in length, produced from the breaking down of larger pieces of plastic such as synthetic clothes, or that are purposely-made for use in industry, or for health and beauty products.

Plastic ingestion by wildlife was first noted in the 1960s, the team explains, adding that microplastic ingestion has come under increased scrutiny since 2010. Since then, microplastics have been found in the guts of fish, marine birds, filter-feeding invertebrates such as oysters, and humans.

Birds of prey, however, have not been studied for microplastic ingestion due to their protected status.

For the study, the team worked with the Audubon Center for Birds of Prey in Maitland, Florida where injured raptor birds are nursed back to health. This gave them a unique opportunity to study the stomach contents of 63 birds found across Florida that were dead when they arrived at the center or died 24 hours after they arrived.

Microplastics were found in the digestive systems of all the examined birds, totalling nearly 1,200 pieces of plastic. The most common microplastics found were microfibers (86%), which come from synthetic ropes and fabrics, and can be released into the environment from clothes-washing.

The most common colors seen were blue and clear, which the team says is likely caused by the birds confusing these colors with prey or materials that would be useful for nesting.

As for solutions, the team says removing plastic waste from open landfills (so birds can’t pick them up), retrofitting water treatment installations to capture microplastics, and switching to natural fibers in the clothing industry could all help.

The paper “Microplastic accumulation in the gastrointestinal tracts in birds of prey in central Florida, USA” has been published in the journal Environmental Pollution.

Birds adapt to climate change by changing their body size, study finds

One in every four species currently faces extinction and much of their vulnerability is linked to climate change, which brings higher temperatures, sea-level rise, more variable conditions, and more extreme weather, among many other impacts.

Animals react to climate change in three ways: they can move, adapt, or die. Many are moving to higher elevations and latitudes to escape warming temperatures, but climate change may be happening too quickly for most species to outrun it.

This means the survival of many species will depend on their capacity to adapt – and that’s what many are already doing. A study by the Australian National University (ANU) looked at how birds and mammals are responding to a warming world.

Animals are not only changing location and advancing the breeding time so as to track the warming seasons but also increasing their body size, despite previous predictions that the size would only get smaller with higher temperatures.

A group of researchers led by Dr. Janet Gardner measured species of 82 Australian bird species located in museums, looking for any changes in the size of their bodies over the last 50 years. They also looked at how climate varied across the range of each species during the same period of time.

“Birds really are the ‘canaries in the coal mine’ when we talk about the impact that climate change is having on animals,” said Gardner. “Because birds can carry only limited body reserves due to the constraints of flight, they can be more vulnerable to climate change than mammals.”

Birds are dealing with climate change by either reducing or increasing their body sizes, the study found, depending on their geographical location and on the type of climate they experience. In very hot and dry weathers, for example, birds were found to increase their size, linked to a lower capacity of small birds to survive to heatwaves.

“With larger body size comes the capacity to carry more body reserves, which may allow individuals to survive longer when exposed to heatwaves and other extreme events,” said Gardner. “However, getting larger has its own costs—get too big and it becomes hard to shed heat effectively.”

Whether animals can change fast enough to keep up with a rapidly warming climate remains an open question and one that requires urgent attention, Dr. Gardner said. “There is a limit to the amount that body size can change without affecting a species’ survival and reproduction,” she said.

The study was published in The Royal Society journal

Predators can learn what food to avoid from watching TV

New research from the University of Cambridge found that blue tits and great tits can learn to avoid unpleasant foods by watching their fellow birds eat on TV.

Two Blue Tits sharing food.
Image credits Dave Croker.

Seeing the ‘disgust response’ in their fellows helped the birds that took part in this study to avoid dangerous or unpleasant foods without having to try them themselves, the team reports. Later on, they recognize distasteful prey by their markings, potentially improving their survival rate.

The findings offer insight into how species share information regarding prey or food socially and help showcase the evolutionary benefits of banding together in groups or flocks.

Foodie shows

“Blue tits and great tits forage together and have a similar diet, but they may differ in their hesitation to try novel food. By watching others, they can learn quickly and safely which prey are best to eat,” said first author Liisa Hämäläinen, formerly a Ph.D. student at the University of Cambridge’s Department of Zoology and now at Macquarie University, Sydney.

“This can reduce the time and energy they invest in trying different prey, and also help them avoid the ill effects of eating toxic prey,”

The team worked with blue tits (Cyanistes caeruleus) and great tits (Parus major), in order to understand how and why prey avoidance behaviour spreads through populations of predators.

Blue tits and great tits forage together in the wild, so have many opportunities to learn from each other. If prey avoidance behavior spreads quickly through predator populations, this could benefit the ongoing survival of the prey species significantly, and help drive its evolution.

Many species of insects use bitter or toxic chemicals to deter predators. They usually advertise this with bright coloring and conspicuous markings. However, these ploys only work after a predator has learned to associate them with ‘undesirable’ prey. The findings of this study, however, shows that predators can learn which prey to avoid by watching other members of their group while trying to consume different insects.

The team showed each bird a video recording of another as it was eating distasteful prey. Some of the recorded birds displayed a disgust response (including vigorous beak wiping and head shaking) which the team hoped would help inform the watchers. This behavior was sometimes edited out to see if it would affect the watchers’ behavior.

The ‘prey’ shown on TV consisted of small pieces of almond flakes glued inside a white paper packet — some of these packets were soaked in a bitter solution. All packets had a marking on the side to help the birds better differentiate between them: a cross symbol that blended into the background for tasty packets, and a conspicuous square for the bitter ones.

When presented with these packets later on, the TV-watching birds (both blue tits and great tits) ate fewer of the bitter ones if they witnessed a disgust response to those packets in the footage, the team reports.

“In our previous work using great tits as a ‘model predator’, we found that if one bird sees another being repulsed by a new type of prey, then both birds learn to avoid it in the future,” said Dr. Rose Thorogood, who led the research.

“By extending the research we now see that different bird species can learn from each other too. This increases the potential audience that can learn by watching others, and helps to drive the evolution of the prey species.”

The paper “Social learning within and across predator species reduces attacks on novel aposematic prey” has been published in the Journal of Animal Ecology.

‘Dancing dragon’ bridges gap between feathered dinosaurs and birds

Paleontologists have recently described the 120-million-year-old fossils belonging to an ancient extinct species that was a bizarre mix between dinosaurs and birds.

Credit: Erick Toussaint/San Diego Natural History Museum.

The fossils of the newly reported species, dubbed Wulong bohaiensis (“the dancing dragon”), were first unearthed from China more than ten years ago, in the fossil-rich Jiufotang Formation. The region is thought to be one of the first habitats where dinosaurs and early birds co-existed.

The species, which is twice as old as T. rex, has been described based on a fantastically well-preserved specimen, whose feathers look trapped in time.

“The new dinosaur fits in with an incredible radiation of feathered, winged animals that are closely related to the origin of birds,” said postdoctoral researcher Ashley Poust of the San Diego Natural History Museum and UC Berkeley. “Studying specimens like this not only shows us the sometimes surprising paths that ancient life has taken, but also allows us to test ideas about how important bird characteristics, including flight, arose in the distant past.”

According to the new study, authored by experts in China and the United States, Wulong is one of the earliest velociraptor relatives and potentially a missing link in the dinosaur-to-bird evolutionary transition.

Wulong bohaiensis, a name that means “Dancing Dragon” in Chinese to reference its active pose. Credit: Ashley Poust.

The dinosaur was about the size of a raven, but double its length, and looked like a dwarfish feathered raptor. Its four limbs must have looked like wings, all balanced by a very long, double-plumed tail. Feathered limbs and tails are what we associate today with modern birds.

Although tiny, Wulong had a fierce-looking narrow face and its mouth was littered with sharp teeth. Its bones were small and light, like a bird’s.

Not too long ago, feathers were thought to have appeared exclusively in birds. However, we now know that many dinosaurs species — the ancestors of today’s birds — had a plumage of some sort. In fact, many key avian features may have evolved even before dinosaurs appeared, in a common ancestor.

Wulong skull. Credit: The Anatomical Record.

Writing in the journal The Anatomical Record, the team of researchers claims that the new dinosaur looks very closely related to the origin of birds.

When it died, the dinosaur was a juvenile, based on its bones that had not fully matured. The feathers, however, resemble those of a mature adult, suggesting that they grew much more quickly than bones, unlike modern birds. It’s possible that the young Wulong needed these tail and limb feathers for some yet unknown purpose.

Jehol biota, the richest fossil deposits in the world and the Chinese region where Wulong was found, was probably one of the most biodiverse habitats for early flying animals. It housed birds, bird-like dinosaurs, and even pterosaurs. Around this time some of the first flowering plants began to bloom.

“There was a lot of flying, gliding, and flapping around these ancient lakes,” says Poust. “As we continue to discover more about the diversity of these small animals it becomes interesting how they all might have fit into the ecosystem.”

“It was an alien world, but with some of the earliest feathers and earliest flowers, it would have been a pretty one.”

African grey parrots will help their peers without expecting anything in return

New research at the Max Planck Institute for Ornithology, Germany found that African grey parrots will help their peers even if they don’t gain anything from it. The findings could help inform how altruism and prosocial behavior evolved in humans.

Image credits Found Animals Foundation / Flickr.

Us humans, along with some of our great ape relatives, like to stick together. Part of that involves helping out those in need, even if we don’t get anything back. Such prosocial behavior helps strengthen the bonds between individual members, thus strengthening the group overall, and improving our collective chances to survive and procreate (the end goal of evolution).

It would be easy to chalk it up to our intelligence — it makes sense to help those in need so that they will help us in turn. To the best of our knowledge however, crows, despite being social and intelligent birds, don’t really help each other out. In an effort to find the root of such prosocial behavior, the team behind the new study worked with two species of parrots and observed whether they would offer help to their peers and if so, under which conditions.

Token of goodwill

“We found that African grey parrots voluntarily and spontaneously help familiar parrots to achieve a goal, without obvious immediate benefit to themselves,” says study co-author Désirée Brucks of the Max Planck Institute for Ornithology, Germany.

Parrots have large brains for their body size, giving them quite a fair share of cognitive oomph. As a group, they are known for having excellent problem-solving skills and, as anyone who has one for a pet knows, a great need for interaction and stimulation.

The team worked with several African grey parrots and blue-headed macaws. For the experiment, the animals were placed in paired-up boxes with holes cut into the sides so that each bird could interact with the researchers and one another. The animals were trained to trade tokens with a human in return for a nut. They could cash the token in themselves or pass it over to their neighbor, allowing the other bird to earn a treat instead.

While both species were eager to trade with the experimenters, only the African grey parrots were willing to give the token to their neighbor. They would do so regardless of the relationship between themselves and their neighbors, the team found. The drive to help someone even if they aren’t a friend is a very prosocial behavior, the team explains.

“It surprised us that 7 out of 8 African grey parrots provided their partner with tokens spontaneously–in their very first trial–thus without having experienced the social setting of this task before and without knowing that they would be tested in the other role later on,” von Bayern explains.

“Therefore, the parrots provided help without gaining any immediate benefits and seemingly without expecting reciprocation in return.”

Another very interesting find was that the parrots seemed to understand whether their neighbor needed help or not. They would only pass a token on if their partner had the opportunity to make an exchange (i.e. the experimenter was interacting with them) but no token to give. Otherwise, they would keep it. They would do this regardless of whether their partner was their friend or not, Bayern explains. However, if they were paired up with a friend, the helper would send even more tokens their way.

As to why the African greys engaged in such behavior while the blue-headed macaws did not, the team explains that it likely comes down to differences in their social structures in the wild.

Regardless of why, the findings show that helpful behavior isn’t an exclusive prerogative of great apes, but can (and did) independently evolve in other lineages. Exactly how widespread it is among the 393 known parrot species remains to be seen. There are still many questions to explore, the team adds: for example, what drives these helpful behaviors in parrots? What motivates them? And how can the birds tell when one of their peers needs help?

Personally, I like to think they’re just nice and considerate, despite their sometimes obnoxious and loud nature.

The paper “Parrots voluntarily help each other to obtain food rewards” has been published in the journal Current Biology.