Baby Jackdaws Learn Which Predators to Fear by Eavesdropping on Their Parents

Nestled inside a cavity nest somewhere in Cornwall, a jackdaw chick has never seen a goshawk. It has never needed to. By the time it fledges, if the adults around it have done their job, it will already know to be afraid of one.

A new study from the University of Exeter's Centre for Ecology and Conservation reveals just how this works - and it is more sophisticated than simple imitation. Jackdaw chicks do not just learn to fear whatever sounds they hear when adults panic. They learn selectively, in ways that suggest evolution has built a filter into their brains.

The Experiment: Alarm Calls in Cornish Nest Boxes

Hannah Broad, who led the study during a Master's by Research at Exeter's Penryn Campus, played recordings of two bird species to chicks aged 20 to 30 days old across 39 nests. One was the Eurasian goshawk - a genuine predator of jackdaws. The other was the American golden plover - a non-threatening shorebird that jackdaws have no reason to fear.

Crucially, Cornwall's jackdaws would have had no prior exposure to either species. Both calls were acoustically novel. That made it possible to test learning in isolation from prior experience.

Each call was played alongside either adult jackdaw alarm calls, which signal real danger, or contact calls, which mean everything is fine. The chicks' responses were measured by how often they raised their heads above their shoulders - a standard vigilance behavior that signals perceived threat.

What the Chicks Learned - and What They Did Not

Chicks that heard goshawk calls paired with alarm calls became roughly twice as vigilant when exposed to goshawk sounds again. They had learned to fear the hawk.

Chicks that heard goshawk calls paired with harmless contact calls showed no such increase. And here is the most telling result: chicks that heard plover calls paired with alarm calls also failed to learn fear. Even when adults sounded the alarm, the chicks did not generalize that fear to an arbitrary non-predator.

This suggests the chicks are not just doing simple associative learning - pairing any sound with any emotional cue. Something in their neural architecture appears to predispose them to link alarm signals specifically with birds of prey. The plover, no matter how many times it was paired with an alarm call, did not trigger the same learning pathway.

Why Nest Life Makes Social Learning Essential

Jackdaws nest in cavities - tree holes, chimneys, rock crevices. This is protective in the early weeks of life, but it means chicks have almost no direct exposure to predators before they fledge. Trial-and-error learning after leaving the nest is dangerous. Getting it wrong once is often fatal.

Social learning from adults bridges that gap. By listening to alarm calls in the safety of the nest, chicks can acquire threat recognition without ever having to face a predator directly. The system is elegant in its efficiency.

"Learning to associate events that occur together by chance 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."

A Finding With Practical Implications for Changing Ranges

Goshawks have been expanding their range across the UK, and Cornwall - currently outside their typical territory - may see them more frequently in coming decades. The jackdaw chicks in this study, raised in a landscape without goshawks, nonetheless showed a primed capacity to learn about birds of prey. If goshawks do arrive in Cornwall, local jackdaw populations may have the cognitive tools to adapt faster than expected.

Professor Thornton noted that rapidly changing environments are shifting species ranges worldwide, and that learning processes like the one examined here might give some species a fighting chance at adapting to new threats.

Some caveats are worth noting. The study measured vigilance behavior, not long-term survival outcomes. Whether chicks that learned to fear goshawk calls in the nest actually performed better after fledging remains an open question. The sample of 39 nests is modest, and behavioral responses in controlled playback experiments do not always predict real-world outcomes cleanly.

Still, the core finding - that social learning in the nest is selective, not indiscriminate - adds meaningful nuance to how we understand early cognitive development in birds. The chicks are not blank slates absorbing whatever they hear. They are, in some sense, already pre-loaded with a rough sketch of what the world's dangers look like.