Jackdaws learn from each other about 'dangerous' humans

SEPTEMBER 24, 2019

by University of Exeter

Jackdaws can learn from each other to identify "dangerous" humans, new research shows.

The birds are known to recognise individual people, and respond differently to those they see as a threat.

In the new study, by the University of Exeter, a person unknown to the jackdaws approached their nest, and scientists played a recording of either a warning call or "contact calls" (suggesting no threat).

The next time the jackdaws saw this person, the birds that had heard the warning call reacted defensively by retuning more quickly to their nests.

"One of the big challenges for a lot of animals is how to live alongside humans," said lead author Victoria Lee, a Ph.D. researcher at the Centre for Ecology and Conservation on Exeter's Penryn Campus in Cornwall.

"People can provide some benefits, such as the food at bird feeders, but in some cases humans are also a threat.

"Being able to discriminate between dangerous and harmless people is likely to be beneficial, and in this case we see jackdaws can learn to identify dangerous people without having had a bad experience themselves."

The study was carried out at three sites in Cornwall, focussing on 34 jackdaw nest boxes.

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Angry birds: Size of jackdaw mobs depends on who calls warning

Date: May 10, 2018

Source:University of Exeter

Summary:Jackdaws recognize each other's voices and respond in greater numbers to warnings from familiar birds than strangers, new research shows.

The birds produce a harsh "scolding call" when they spot a predator, calling fellow jackdaws to mob the intruder and drive it away.

University of Exeter researchers have discovered that each bird has a unique call, and the size of the mob depends on which bird calls the warning.

The scientists played recordings of individual calls and found that the largest mobs assembled when birds heard the cry of a member of their own colony.

"Joining a mobbing event can be dangerous, as it involves approaching a predator, so it makes sense for individuals to be selective in whom they join. Our results show that jackdaws use the ability to discriminate between each other's voices when deciding whether to join in potentially risky collective activities," said Dr Alex Thornton, of the Centre for Ecology and Conservation on the University of Exeter's Penryn Campus in Cornwall.

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Jackdaws flap their wings to save energy

Date: August 11, 2017

Source: Lund University

Summary:

For the first time, researchers have observed that birds that fly actively and flap their wings save energy. Biologists have now shown that jackdaws minimize their energy consumption when they lift off and fly, because the feathers on their wing tips create several small vortices instead of a single large one. The discovery could potentially be applied within the aeronautical industry.

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Jackdaws strip straw from £100,000 re-thatched roof of historic National Trust barn

National Trust conservationists try 'umpteen solutions' that have all failed to problem of birds picking apart roof of Grade I-listed Wiltshire barn

Sponsored by BT

By Agency

8:47AM GMT 03 Mar 2016

The National Trust is fighting to save the £100,000 thatched roof of a historic barn at a World Heritage site from jackdaws that tear out the fresh straw to make their nests.

The roof of the Grade I-listed Tithe Barn at Avebury, Wiltshire, was re-thatched just three years ago. But, since then, jackdaws have been picking it apart - but only taking the newly-added straw, which is cleaner and drier for their nests.

Experts have tried several ways of stopping the birds, but they have all failed so far. Conservationists at the National Trust, which owns the 17th-century barn, are trying to find a long-term solution.

"We've tried umpteen solutions to the problem... eventually they've all failed. I'm beginning to tear my hair out. It's so frustrating"

National Trust building surveyor Karl Papierz

Ed Coney, who re-thatched the roof in 2013, called the damage "soul destroying".

He said: "We did the job and were very proud of it and everything was fine, and then slowly it's been pulled to pieces."

The barn was originally a threshing barn and stands in the centre of the famous Avebury stone circle. It is now home to a museum filled with archaeological finds and interactive displays.

National Trust building surveyor Karl Papierz, said: "We've tried umpteen solutions to the problem... eventually they've all failed. I'm beginning to tear my hair out. It's so frustrating.

"We don't know why they are doing this, they only take a few bits for nesting, most is simply pulled and discarded.

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Jackdaws protect their nests 'with bright eyes'

By Ella Davies

Reporter, BBC Nature

Jackdaws' conspicuous bright eyes frighten off their competitors, according to scientists.

Researchers from the University of Cambridge, UK, tested whether the dark birds' striking blue-white eyes help them to protect nest sites.

They found that jackdaws avoided nest boxes when they could see the eyes of a jackdaw inside.

Experts suggest this is the first evidence that bright eyes could act as signals in the bird world.

The results were published in the Royal Society journal Biology Letters.

Jackdaws are members of the corvid family, which includes birds such as crows, ravens and jays, and are known for their intelligence.

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