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

May 10, 2018, University of Exeter
Jackdaws in flight. Credit: Alex Thornton

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

The 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 .

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 .

"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.

"We also found a positive feedback loop - if birds joining a mob made alarm calls of their own, this in turn caused more birds to join in, magnifying the size of the mob."

Jackdaws. Credit: Victoria Lee

The researchers studied wild jackdaws, a highly social member of the crow family, as part of the Cornish Jackdaw Project, a long-term study of jackdaw behaviour and cognition in sites across Cornwall.

In playbacks at nest-box colonies during the breeding season, they broadcast the warning calls of a resident from each nest-box, another member of the same colony, a member of a different colony, and a rook (a species that often associates with jackdaws).

Jackdaws were most likely to respond to a warning from a bird from the resident nest-box owner, followed in turn by other colony members, non-colony members and rooks.

Responses were also influenced by caller sex, with jackdaws less likely to echo a warning if the caller was a female stranger from a different colony.

The paper, published in the journal Scientific Reports, is entitled: "Caller characteristics influence recruitment to collective anti-predator events in ."

Explore further: First in non-primates: Research shows jackdaws use eyes for communication

More information: Richard D. Woods et al, Caller characteristics influence recruitment to collective anti-predator events in jackdaws, Scientific Reports (2018). DOI: 10.1038/s41598-018-25793-y

Related Stories

Research shows jackdaws can recognise individual human faces

August 12, 2015

When you're prey, being able to spot and assess the threat posed by potential predators is of life-or-death importance. In a paper published today in Animal Behaviour, researchers from the University of Cambridge's Department ...

Crows found able to distinguish between human voices

May 16, 2012

(Phys.org) -- Researchers at the University of Vienna have discovered that carrion crows are able to distinguish between familiar and unknown human voices. They also found, as they write in their paper published in the journal ...

Bird can 'read' human gaze

April 2, 2009

We all know that people sometimes change their behavior when someone is looking their way. Now, a new study reported online on April 2nd in Current Biology, a Cell Press publication, shows that jackdaws—birds related to ...

Recommended for you

Archaeologists discover Incan tomb in Peru

February 16, 2019

Peruvian archaeologists discovered an Incan tomb in the north of the country where an elite member of the pre-Columbian empire was buried, one of the investigators announced Friday.

What rising seas mean for local economies

February 15, 2019

Impacts from climate change are not always easy to see. But for many local businesses in coastal communities across the United States, the evidence is right outside their doors—or in their parking lots.

The friendly extortioner takes it all

February 15, 2019

Cooperating with other people makes many things easier. However, competition is also a characteristic aspect of our society. In their struggle for contracts and positions, people have to be more successful than their competitors ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.