Jackdaw chicks listen to adults to learn about predators

(Press-News.org) Jackdaw chicks learn about predators by listening to adults, new research shows.

Scientists played recordings of predator calls to chicks in their nests – and paired the sounds with either adult jackdaw “alarm” calls or “contact” calls that indicate no danger.

Chicks that heard predator sounds paired with alarm calls learned to fear the predator – becoming more vigilant on hearing that sound again – while chicks that heard contact calls did not.

The study, by researchers at the University of Exeter’s Centre for Ecology and Conservation, also tested the effects of a non-predatory birdcall – and found chicks didn’t learn to fear this even when it was paired with alarm calls.

This suggests evolution has shaped learning processes to ensure only “biologically meaningful” links are learned – so animals don’t waste energy responding to things that pose no threat.

“Our study shows that nestling jackdaws can learn about dangers they might encounter in the future by listening to adults,” said Hannah Broad, who led the study during a Master’s by Research at Exeter’s Penryn Campus in Cornwall.

“As they nest in cavities, jackdaws are fairly safe as nestlings. However, learning through trial-and-error after leaving the nest can be dangerous – so social learning as a chick could be highly valuable.”

The recorded birdcalls came from a possible predator of jackdaws, the Eurasian goshawk, and a non-predator, the American golden plover.

The study took place in Cornwall, UK, where sightings of these species are exceptionally unlikely – so the jackdaw chicks would not have heard their calls before.

However, the reaction to the goshawk call (when combined with adult jackdaw alarm calls) suggests jackdaws have an evolved predisposition to learn about birds of prey.

Jackdaw chicks became about twice as vigilant in response to goshawk calls – with vigilance measured by chicks raising their heads above their shoulders.

“Learning to associate events that occur together by chance – for example becoming scared of any birdcall heard at the same time as alarm calls – could cause chicks to learn the wrong information,” said Professor Alex Thornton, from Exeter’s Centre for Ecology and Conservation.

“The chicks in our study learned to fear goshawk calls due to social learning from adults, but our findings suggest evolutionary processes may tailor what can be socially learnt.”

With goshawks expanding their range in the UK, Cornwall’s jackdaws could soon be exposed to these predators.

Professor Thornton said: “As a result of rapidly changing environments, the ranges inhabited by many species are changing.

“Learning processes like the one examined in this study might give species a chance to adapt to new threats.”

The chicks in the study were 20-30 days old, and sound was played at 39 nests in total.

The study, funded by the Leverhulme Trust, is part of the Cornish Jackdaw Project.

Hannah Broad was awarded the Vic Simpson Award for Student Research on Birds in Cornwall for her work.

The paper, published in the journal Biology Letters, is entitled: “Socially learnt predator recognition in nestling jackdaws.”

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