Jackdaw Chicks Learn About Predators Before Leaving the Nest

For many animals, acquiring incorrect information can be fatal. A young bird that cannot identify a predator may have little chance of surviving once it leaves the nest.

New research involving jackdaws indicates that chicks start learning about danger far sooner than previously thought. While still in the nest, they can identify animals that could pose a threat by closely listening to adult birds’ calls.

Scientists at the University of Exeter’s Centre for Ecology and Conservation found that jackdaw chicks learn about predators through sound.

By attending to warning calls made by adults, chicks begin developing knowledge of threats they may face later in their lives.

Jackdaw communication and predator recognition

Jackdaws are small birds in the crow family, recognised for their social lives and frequent communication with other members of their groups.

Adult jackdaws make distinct calls for different circumstances. Some function as alarm calls when a threat is present, whereas others are ordinary contact calls that help birds remain in touch when there is no nearby danger.

Researchers wanted to establish whether jackdaw chicks could use these vocalisations to learn about predators before they had even left their nests.

Because jackdaws generally develop in enclosed spaces, including holes in trees and buildings, nestlings are comparatively secure early in life. Once they emerge from the nest, however, predators represent a genuine risk.

Gaining this knowledge at an early stage could help young birds survive this hazardous period.

How jackdaw chicks learn about danger

To investigate, the researchers conducted an experiment with jackdaw chicks in Cornwall, United Kingdom. Recordings were played to the chicks while they were still inside their nests.

The recordings featured the call of a Eurasian goshawk, a bird of prey capable of hunting jackdaws. The researchers matched this predator call with two separate types of adult jackdaw vocalisation.

At certain nests, the goshawk call was played alongside adult alarm calls, which communicate danger. At other nests, it was paired with routine contact calls, which signal that conditions are safe.

The researchers subsequently monitored the chicks’ responses when they heard the predator sound again.

The effect of adult warning calls

The findings revealed a marked contrast between the two groups. Chicks that had heard the predator call alongside adult alarm calls were more alert when the predator call was replayed later.

Scientists assessed alertness by recording whether chicks lifted their heads above their shoulders. This position indicates that a bird is searching its surroundings for potential danger.

When the predator sound was played again, chicks that had been exposed to alarm calls displayed roughly twice as much vigilance. By comparison, chicks that had heard the predator call with contact calls did not have the same fearful response.

“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.

Why early learning is valuable

Young jackdaws are usually sheltered inside nest cavities at the beginning of their lives. After fledging, though, their surroundings become considerably more dangerous. They must then identify predators quickly and respond rapidly enough to get away.

“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,” Broad explained.

By learning from adult birds, chicks can avoid making dangerous errors later on. Rather than recognising predators through risky direct encounters, young birds can gain important knowledge by listening.

Evolution’s role in learning

The scientists also examined another bird call to explore how this learning operates. They played the call of an American golden plover, a species that does not prey on jackdaws.

Even when the American golden plover call was paired with alarm calls, the chicks did not learn to fear it. The result indicates that evolution has influenced the way animals learn. Learning mechanisms may prioritise relevant threats instead of arbitrary associations.

“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.

“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.”

Adapting to changing environments

The study also underlines how learning could enable animals to adjust to changing environments. The Eurasian goshawk has recently extended its range in the United Kingdom.

Jackdaws in Cornwall seldom encounter this predator at present, although such encounters could become more frequent in future.

Professor Thornton said learning may assist species in responding to these emerging threats.

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

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

The Cornish Jackdaw Project research

The experiment was conducted at 39 jackdaw nests in Cornwall, and every chick involved was between 20 and 30 days old.

As sightings of Eurasian goshawks and American golden plovers are exceptionally uncommon in the area, the chicks had almost certainly never previously heard either call.

The work is part of the Cornish Jackdaw Project and was funded by the Leverhulme Trust. For this research, Hannah Broad also received the Vic Simpson Award for Student Research on Birds in Cornwall.

The study demonstrates that birds can start acquiring survival knowledge while they are still very young and well before they leave the nest. Listening carefully to adult calls may enable young jackdaws to recognise danger and remain safe in the wild.

The findings were published in Biology Letters in a paper entitled “Socially learnt predator recognition in nestling jackdaws.”