Study shows link between health and size of social group

Date: November 14, 2019

Source: Anglia Ruskin University

A new study has found that crows living in large social groups are healthier than crows that have fewer social interactions.

The research, led by Dr Claudia Wascher of Anglia Ruskin University (ARU), has been published this week in the journal Animal Behaviour.

Dr Wascher and her colleagues studied a population of captive carrion crows over a six-year period. They monitored the behaviour of the crows in different sized groups and measured friendship by ranking the birds using a sociality index.

At the same time, they studied the crows' droppings to measure for the presence of coccidian oocyst, a gastrointestinal parasite that can represent an important health threat for birds.

Increased exposure to parasites and disease transmission is considered as one of the major disadvantages of group living. This new study, however, shows the opposite effect.

The researchers found that crows with strong social bonds, living with more relatives, and in larger groups, excreted a significantly smaller proportion of droppings containing parasites than less sociable crows.

The study did not find a connection between health and the crow's dominance within the group, but found that male crows (33%) were slightly more likely to carry the parasite than females (28%).

Dr Wascher, Senior Lecturer in Biology at Anglia Ruskin University (ARU), said: "Crows are a highly social bird and we found that crows with the strongest social bonds excreted fewer samples containing coccidian oocyst, which is a common parasite in birds.

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Video shows group of crows repeatedly 'ice skating' down frosty roof of Cork on Ice

By

Andrew Byrne Video Editor

A group of crows were filmed repeatedly "ice skating" down an icy roof on Monday morning.

The video was filmed in the early hours of the morning in Cork city as the birds used the ice covered roof of Cork on Ice to slide down.

Originally, the video shows just one bird performing the unusual act but as the camera spans across the roof a number of other crows are seen doing the same thing.

The footage was filmed by Paddy O'Shea on the Centre Park Road before posting the video on Twitter.

The freelance lighting technician told the Irish Mirror: "I was working on the lighting set up for Cork on Ice so I was on site early.

"There was a bunch of crows messing about on the ice covered roof of the marquee.

"I thought it was very funny that the crows were ice skating on the roof of the Cork ice rink."

He added: "We'll have to charge them next time."

The video has been praised online with one Twitter user saying: "They're clever yokes!"

While another added: "Coup for city as Winter Crow-lympics hosted in Cork."

The ice rink opens at the end of the week on the 22nd of November but these "early birds" just couldn't wait.

Watch video

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Crows consciously control their calls

AUGUST 27, 2019

by Public Library of Science

Crows can voluntarily control the release and onset of their calls, suggesting that songbird vocalizations are under cognitive control, according to a study published August 27 in the open-access journal PLOS Biology by Katharina Brecht of the University of Tübingen, and colleagues.

Songbirds are renowned for their acoustically elaborate songs; these show a degree of flexibility, potentially indicating that they are under conscious control. However, the observed variability in vocalizations might simply be driven by involuntary mechanisms, and need not be based on cognitive control. In the new study, Brecht and colleagues directly tested the idea that songbirds deliberately control their calls, in the sense that they can be emitted or inhibited at will, as opposed to being knee-jerk responses to food, mates, or predators.

The findings show that trained carrion crows (Corvus corone), songbirds of the corvid family, can exert control over their calls in a goal-directed manner. In a detection task, three male carrion crows rapidly learned to emit calls in response to a visual cue(colored squares) with no inherent meaning ("go-trials"), and to withhold calls in response to another cue. Two of these crows were then trained on a task with the cue colors reversed, in addition to being rewarded for withholding vocalizations to yet another cue ("nogo-trials").

Read on

Urban living leads to high cholesterol... in crows

AUGUST 26, 2019

by American Ornithological Society

Crows living in urban environments with access to discarded human food have higher blood cholesterol levels than their rural cousins. Credit: Andrea Townsend

Animals that do well in urban areas tend to be the ones that learn to make use of resources such as the food humans throw away. But is our food actually good for them? A new study published in The Condor: Ornithological Applications suggests that a diet of human foods such as discarded cheeseburgers might be giving American Crows living in urban areas higher blood cholesterol levels than their rural cousins.

Hamilton College's Andrea Townsend and her colleagues sampled the blood cholesterol levels of 140 crow nestlings along an urban-to-rural gradient in California, returning to track their survival rates after they fledged. They found that the more urban the environment, the higher the blood cholesterol of the crow nestlings raised there. To directly test the effects of human food, the researchers also provided nestlings in a rural New York population with a regular supply of McDonald's cheeseburgers and compared their blood cholesterol levels with those of nearby crows who had to fend for themselves. The crows who were fed cheeseburgers ended up with higher cholesterol levels than their neighbors, similar to those of the urban crows in California.

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After using tools, crows behave more optimistically, study suggests

AUGUST 23, 2019

by Peter Reuell, Harvard University

It's no secret crows are smart. They're notorious for frustrating attempts to keep them from tearing into garbage cans; more telling, however, is that they are one of the few animals known to make tools.

But would you believe doing it actually makes them happy?

That's the finding of a recent paper, co-authored by Dakota McCoy, a graduate student working in the lab of David Haig, George Putnam Professor of Biology, who found that crows behaved more optimistically after using tools. The study is described in an Aug. 19 paper in Current Biology.

"What this suggests is that, just the same way we enjoy something like solving a crossword, they actually enjoyed simply using a tool," McCoy said. "I think it suggests there's a lot more going on in that little head than we think. They get satisfaction out of doing things they're good at, have trained for their whole lives, and that they use frequently."

While tool use in the animal kingdom is not unheard of—chimps use sticks to "fish" for termites and other animals use rocks to smash open nuts or shells—New Caledonian crows stand out for manufacturing multiple complex tools and regularly refining their designs.

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Dozens of dead birds found floating in Perthshire loch

11 July 2019

The discovery of about 100 dead birds in a Perthshire loch has been reported to police, amid fears of a possible illegal cull.

Dozens of carcasses - believed to be crows - were reported floating on Loch Freuchie, west of Dunkeld.

Scottish Natural Heritage (SNH), which licenses the culling of crows and ravens, was informed as a result.

A spokeswoman said the discovery had been reported to police for further investigation.

Brenda Henderson from Crieff told The Courier newspaper: "They all looked like young crows. There must have been close to 100. It was quite alarming."

An SNH spokeswoman described the incident as "disturbing", but said it was difficult to determine exactly what had led to the birds' deaths.

She added: "We strongly encourage anyone who believes they have witnessed wildlife crime to contact the police as soon as possible.

"In cases such as these we advise that dead birds should not be handled and pets be kept away. We will assist the police with any inquiries they make."

Source

Woodpigeons and crows can no longer be freely killed in England

Natural England scraps general licence to kill ‘pest’ birds after launch of legal challenge

Patrick Barkham

Wed 24 Apr 2019 12.05 BSTLast modified on Thu 25 Apr 2019 01.00 BST

 “Pest” bird species such as crows, woodpigeons and jays can no longer be freely killed in England after the government’s conservation watchdog revoked the licence permitting it.

The move by Natural England came after a challenge to the legality of the “general licence” by a new environmental group, Wild Justice, created by conservationists Mark Avery, Ruth Tingay and Chris Packham.

Natural England now plans to introduce a legal system of licences to allow 16 species of birds, including rooks, magpies, Canada geese and non-native parakeets, to be controlled. In the meantime, anyone wanting to control these species must apply for an individual licence, as they are required to if seeking to kill other more protected bird species.

Wildlife campaigners have greeted the decision, which came on Tony Juniper’s first day as the new chair, with delight, but many farmers – and some conservationists – were dismayed.

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Crows go on panty raids in Melaka, dozens of reports lodged

Thursday, 11 Apr 20195:08 PM MYT

by r.s.n.murali

MELAKA: Crows have become a menace here, driving residents to despair while leaving one local councillor trying to figure out why the birds are targeting women’s undies.

Melaka Historic City (MBMB) councillor Tan Chin Gwan said he was perplexed by why crows were snatching undergarments placed on clotheslines, especially at the city's commercial hub of Kota Laksamana.

“These thieving birds are a menace as they have swooped down and snatched dozens of panties since June last year.

“I have received more than a hundred reports of crows terrorising condominiums and high-rise residential areas in Kota Laksamana in the last 10 months, and 20% of the complaints have been on missing panties,” he told The Star here on Thursday (April 11).

“I am still baffled by why these crows are snatching panties, and where they go to hide them,” he admitted.

Tan added that crows have been brazenly flying into hotel premises, eateries and schools to steal food, scaring people in the process.

He said the bird population has grown so much that the MBMB pest control unit has been forced to cull them.

Read more at 

Chilling moment dozens of crows surround bizarre UFO in sky

HUNDREDS of crows were spotted circling a mysterious black object, sparking concerns of an alien invasion online.

By Emmet McGonagle / Published 20th December 2018

In the footage, a giant murder of crows can be seen circling a strange object in the sky.

The birds fly rapidly back and forth in the suburban street, leading one witness to conclude the phenomenon must be the result of “aliens”.

The terrifying clip was posted online by theorist Seed To Shatter, but has gained viral status thanks to conspirators Blake and Brett Cousins.

In a video posted to their YouTube channel thirdphaseofmoon, Blake maintains the birds were attracted by “a magnetic field surrounding the unusual object”.

The theorist questions whether the object could just be a balloon, but quickly changes his mind as it doesn’t explain why the birds would have such a strong response to the object.

Estimating the object to be between 15-25 feet long, the pair conclude the object is indeed a UFO.

And viewers agree the object is “extraterrestrial”.

One viewer pointed out the crows are “incredibly disturbed” by the eerie object floating among them in the sky.

Watch video

Crows using roof top to crack open walnuts is driving dog crazy

The homeowner is none too happy either. What can be done to discourage the crows and their pounding?

Large flocks of crows can cause issues for humans ranging from excessive noise, harassment and raiding of gardens, orchards and field crops.

By JOAN MORRIS | jmorris@bayareanewsgroup.com | Bay Area News Group

PUBLISHED: September 17, 2018 at 7:00 am | UPDATED: September 17, 2018 at 7:05 am

DEAR JOAN: I think it’s called a murder of crows, but maybe I just want to murder the crows.

Every year we get 40 or 50 crows eating breakfast on our roof and it drives Chrissie, our normally non-vocal bichon frise, crazy. The crows bring large, nut type husks the size of walnuts and use our roof as an anvil to break them open.

The pounding on the roof by so many crows sounds like we have a family of raccoons up there, and as you can expect, the crows don’t seem to get along with each other as they caw and chase each other nonstop, dropping the husks that then roll across the roof and accumulate in the rain gutters.

Poor Chrissie isn’t very happy with the knocking and pounding on the roof and neither am I as I don’t know what kind of damage they might be doing up there. It I step outside and rap on the rain gutter with a long cardboard tube, the crows take flight and the sky turns black for a few moments as they scatter, only to return 10 minutes later.

I’m guessing that the parents are teaching their youngsters how to hunt for food but do you have any ideas how I might discourage the crows from turning my roof into a Denny’s Grand Slam breakfast venue?

Art Mayoff, Benicia

DEAR ART: Keeping certain birds out of your yard is not an easy task, unless maybe you build a glass dome over your house, and then I think the crows might create another problem for you that would require constant window washing.

There are devices you can attach to the eaves and ridge lines of your house, common roosting spots for birds, that are intended to keep them off. The bird spikes are just what the name implies — spikes that would make perching very uncomfortable. However, as the crows are doing more than roosting, they could continue to use your roof as a giant nutcracker.

You could hang Mylar ribbons and sparkly disks above your roof, but crows soon figure out those are nothing to worry about.

How about creating a place in your yard for the crows to use? You could build a platform, install large rocks or other hard surfaces to substitute for your roof. Place some bird seed and walnuts out to attract them to the spot. As crows seem to do exactly what we don’t want them to do, be sure to tell them they need to stay off.

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Where do crows go in winter?

Date:  August 8, 2018

Source:  American Ornithological Society Publications Office

Summary:

'Partial migration' -- where some individuals within a population migrate and some don't -- is common among birds, but scientists know very little about how it actually works. A new study tracks where American Crows go during the winter and shows that while individuals are consistent in whether they migrate or stay put, partial migration might give them enough flexibility to adapt to changing environmental conditions.

Read on  

Counting crows: Vancouver college maps thousands of attacks

Tool launched in response to dive-bombing birds documents 2,500 attacks since 2016

Ashifa Kassam in Toronto

Fri 20 Jul 2018 09.32 BSTLast modified on Sat 21 Jul 2018 19.48 BST

It was a crow fiercely protecting its nest – and repeated complaints of it dive-bombing and swooping – that prompted the idea.

“Just about every day someone would come in and say: ‘I got smacked in the back of the head,’ or ‘Mary got smacked in the back of the head,’” said Jim O’Leary, a teacher at Langara College in Vancouver, Canada.

“I was thinking to myself: I know crows are smart but we’re pretty smart too. Isn’t there something that I can do about this?”

The result was CrowTrax, an online tool that since 2016 has documented about 2,500 crow attacks in the Metro Vancouver region, nearby Victoria and around the world.

O’Leary, who teaches a course on geographic information systems (GIS), initially envisioned the site as a way to show his students how such systems could be used to map and store spatial data.

“But it kind of took on a life of its own. Because most people really don’t care about GIS; they just care about crows,” he said.

Within hours of launching the site, reports began pouring in. About 1,000 anecdotes came in during the site’s first year, and 1,500 the next year.

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Crows Are Always Jerks to Ravens, Research Confirms

A new study shows that although crows are smaller than ravens, they are almost always the aggressors when the two species interact.

BY ANNIE ROTH

PUBLISHED JULY 4, 2018

LIVING ALONGSIDE A group of crows can be murder for a raven.

Across North America, common ravens are regularly harassed by gangs of crows, according to a new study published Wednesday in The Auk: Ornithological Advances. In 97 percent of reported interactions between crows and ravens, scientists report, crows were the aggressors.

This grudge match goes way back. In North America, ravens are both competitors and predators of the crow. Given the chance, brazen, jet-black ravens will happily make a meal out of a crow’s clutch of eggs. And one on one, a crow doesn’t stand a chance against a raven, which can reach up to three times a crow’s size and weight. (Read more about how ravens hold grudges against humans.)

But what crows lack in size, they make up for in numbers. Ganging up “gives crows the upper hand,” says Ben Freeman, postdoctoral fellow at University of British Columbia and lead author of the study.

Read on  

Crows hold "funerals" for their dead and this very weird experiment revealed why

According to researcher Kaeli Swift of the University of Washington's Avian Conservation Laboratory, crows hold "funerals." When they see a corpse of their own kind they gather together and squawk loudly. To determine what they may be doing, Swift displayed a taxidermied dead crow to other crows. On some days though, she wore a creepy mask and wig. After multiple experiments with and without her disguise or the dead bird, the crows appeared to remember "the experience with the mask and dead crow and now connected the area with danger." From Deep Look:

And here’s what Swift said makes that really interesting: These new mobs (she encountered even weeks later) contained crows that had never seen the masked Swift with the dead crow. But they still learned to avoid the masked figure.

Learning directly from each other, rather than through individual experience, is called social learning.

“By participating in these funerals, crows can get information about new dangers without taking the risk,” Swift said.

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Crafty crows know what it takes to make a good tool

New study provides surprising insights into how crows manufacture their hooked foraging tools

Date:  December 7, 2017

Source:  University of St. Andrews

Biologists at the University of St Andrews have discovered how New Caledonian crows make one of their most sophisticated tool designs -- sticks with a neatly-shaped hooked tip.

New Caledonian crows are the only species besides humans known to manufacture hooked tools in the wild. Birds produce these remarkable tools from the side branches of certain plants, carefully 'crafting' a crochet-like hook that can be used for snagging insect prey.

The study, published in Current Biology today (7 December), reveals how crows manage to fashion particularly efficient tools, with well-defined 'deep' hooks.

Continued  

Rooftop wiretap aims to learn what crows gossip about at dusk

Date:  December 5, 2017

Source:  University of Washington

Summary:

An interdisciplinary team is using a covert sound-based approach, worthy of an avian CSI, to study the link between crows' calls and their behavior.

What are crows saying when their loud cawing fills a dark winter's evening? Despite the inescapable ruckus, nobody knows for sure. Birds congregate daily before and after sleep, and they make some noise, but what might be happening in those brains is a mystery.

Curious about these raucous exchanges, researchers at the University of Washington Bothell are listening in. They are placing equipment on the roof of their building -- a meeting place for some of the thousands of crows that sleep in nearby campus trees -- and using a sort of computerized eavesdropping to study the relationship between calls and the birds' behavior.

"With audio alone, our team is able to localize and record the birds remotely, and in dim light that makes this situation less suitable for video tracking," said Shima Abadi, an assistant professor at UW Bothell's School of Science, Technology, Engineering & Mathematics. "It's still a challenging task, but we can use the audio signals to look for patterns and learn more about what the birds may be communicating."

Read on  

Betty the wire-bending crow may have been less insightful than previously believed

August 10, 2016 by Bob Yirka 

A team of researchers with the Centre for Biological Diversity, School of Biology, University of St Andrews, in the U.K. has found that the seemingly clever wire bending abilities of New Caledonian crow Betty back in 2002 may not have been as impressive as scientists at the time thought. They note in their paper published in Royal Society Open Science that while conducting field experiments with other crows of the same species in their native environment, several crows exhibited the same behavior as Betty, suggesting that her behavior might have been more responsive than insightful.

The video of Betty (made by a team at the University of Oxford) using a wire in attempting to retrieve a bucket of meat from inside a bottle captivated the science community when it was first revealed—after poking at the bucket for a minute or so, she pulled the wire out of the bottle, bent the tip to resemble a fish hook, dropped it back into the bottle and then hooked the handle of the bucket, allowing her to pull the meat up and out so she could eat it. The impression was that the crow had come up with a completely novel solution to a problem she had never encountered before—all on the spur of the moment. Such an ability was seen as an example of comparative cognition and high intelligence. But now it appears that Betty may have been engaging in an activity that others of her kind have been doing for quite some time.

To gain a better understanding of Betty's abilities, the researchers ventured to New Caledonia, an archipelago in the South Pacific and home to New Caledonian crows. There, they temporarily captured several specimens and placed them in an aviary. Once inside, the birds discovered that food had been placed in multiple hideaway spots and required the use of tools for retrieval. As the team observed, the birds got right to work using twigs as extensions to reach and retrieve the food. But some also bent the twigs in very nearly the same way as Betty had done in the video, which the researchers suggest made retrieval a bit easier.

These findings suggest that rather than using insight, Betty might have simply been following routines regularly used by members of her species, though the team notes, it does not rule out the possibility that she did understand what she was doing while she was doing it, as did the other birds they observed.

Read more at: 

Wild crows are pretty good at making tools, study finds

AUGUST 10, 2016

by John Hopton

Understanding of crows' crafting and use of tools has been slow to progress, but just took a major step forward through observing wild New Caledonian crows.

It was back in 2002 that a captive crow, Betty, blew scientists' minds as they watched the bird bend twigs into hooks in order to extract buried food.

The University of Oxford, UK, researchers wondered if the trait may have emerged in captivity, but a new study of the wild crows from New Caledonia in the South Pacific suggests the trait may in fact be part of the birds' natural behavior.

Along with crows, captive rooks have previously been seen to fashion tools in such a way. Wild crows have also long been known to use twigs to get at food. But seeing wild birds fashion tools represents a new development.

Dr. Christian Rutz, from the University of St Andrews in Scotland, who is lead author of the new study published in the journal Open Science, explained how short-term capture of crows from the tropical forests of New Caledonia helped to aid understanding.

Rutz said: "This means we can test them under highly controlled experimental conditions - but the kind of experiments we do there, they don't look at how smart these animals are, they ask what sort of tool behaviour they express naturally."

How did they test for this ability?

The team used wooden logs with appealing food buried inside them, which were presented to the crows.

"The only other thing we provided in the aviary was the plant material, which we knew they naturally used for tool-making in the wild," explained Rutz.

"So the task was very simple, we asked our subjects to make tools, then use these tools to extract the hidden food."

An impressive 10 of the 18 wild-caught birds made tools from the twigs.

It wasn't entirely necessary for the birds to make tools in order to reach the food, but many of them did so anyway.

We think the bending helps with the tool ergonomics," said Rutz.

Read more at 

In a race for Cheetos, magpies win, but crows steal

August 11, 2016

Black-billed magpies and American crows, both members of the clever corvid family of birds, have adapted comfortably to life in urban and suburban communities. In Jackson Hole, Wyoming, the two species often nest nearby each other in backyards and parks. Nesting near their much larger crow cousins affords magpies a margin of extra safety from a common enemy—ravens, an even larger corvid species.

"Ravens are notorious nest raiders," said Rhea Esposito, an educational program leader at the Cary Institute of Ecosystem Studies. During her graduate work at the University of Louisiana at Lafayette, Esposito studied how birds associate during nesting season. Smaller birds sometimes nest near larger species to benefit from their more aggressive defense against predators. Research has tended to focus on the protection side of the relationship. But what about competition? Do magpies pay a food penalty for nesting near larger rivals? Or do the smaller birds compensate with bold pursuit of new food sources?

To find out which of the two corvids were more intrepid snack scouts, Esposito presented breeding pairs with a set of Cheetos challenges. She will present her results today at the 101st Annual Meeting of the Ecological Society of America in Fort Lauderdale, Florida, during a session on animal Behavior.

"Cheetos are not the healthiest food, but the birds like them a lot," said Esposito. "And because they are bright orange, it was really easy to observe when the birds completed the task."

Esposito set out Cheetos near nests and settled in to watch the birds fly down to investigate. Magpies moved on the unfamiliar food an average of 20 seconds faster that crows, which eyed the orange treats with more suspicion, pausing longer before picking them up. Once having identified Cheetos as food, however, crows were more apt to steal.

Read more at:

Crowds of crows spread C. jejuni: Are humans vulnerable?

Date: June 4, 2016

Source: American Society for Microbiology

Crows are smart, highly social animals that congregate in flocks of tens of thousands. Such large, highly concentrated populations can easily spread disease -- not only amongst their own species, but quite possibly to humans, either via livestock, or directly. On the campus of the University of California, Davis, during winter, approximately half of the 6,000 American crows that congregated at the study site carried Campylobacter jejuni, which is the leading cause of gastroenteritis in humans in industrialized countries, which could contribute to the spread of disease. The research is published in Applied and Environmental Microbiology.

The investigators posited that the crows' daily wanderings contributed to C. jejuni's spread. To track the crows, they trapped a small number of individuals and attached tiny GPS devices to diminutive backpacks. They affixed these to the birds with harnesses that looped around each wing to attach at the breast. The additional weight represented less than one twentieth that of the crows.

The crows' favored destinations were areas with easy access to food, such as a dairy barn, and a primate research center. "This movement pattern, coupled with high infection rates, suggests that crows could play an important role in transmission from wild birds to domestic animals and, ultimately, to humans," said first author Conor Taff, PhD.

Crows are also strong flyers, and able to spread contamination far from the roost.

Crows' social behavior also probably contributes to the pathogen's spread. Their communal winter roosts can pack thousands of crows into a few trees each night, said Taff, a postdoctoral researcher at Cornell University, Ithaca, NY, who conducted some of the research while he was a postdoctoral fellow at the University of California, Davis. And crowds of crows, opportunistic omnivores, forage together, defecating where they eat. "These things together probably explain why crows have such high prevalence of infection compared to other wild birds," said Taff.

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