Squirrels eavesdrop on birds to find out when the coast is clear – study

We might not be able to tell one bird tweet from another, but to grey squirrels a certain call signals it is safe to come out.

Grey squirrels eavesdrop on the chatter of nearby songbirds to figure out when danger has passed, scientists say.

They wait and listen for when the birds feel safe enough to start tweeting casually after the earlier predator call.

When the squirrels hear the more relaxed call, it reassures them to come off high alert.

A squirrel in St James’s Park, London (Kirsty O'Connor/PA)
(Kirsty O’Connor/PA)

Scientists in the US observed how 54 wild eastern grey squirrels in public parks and residential areas in Ohio responded to threats.

They simulated potential danger by playing a recording of a red-tailed hawk – a common predator of squirrels and small birds.

This was followed by a playback of either multi-species songbird chatter or ambient sounds lacking bird calls.

The behaviour of each squirrel was monitored for three minutes.

Published in the PLOS ONE journal, the study found that all squirrels showed an increase in predator vigilance behaviours, such as freezing, looking up or fleeing, after they heard the hawk’s call.

However, the squirrels that were played bird chatter afterwards displayed fewer vigilance behaviours and returned to normal levels of watchfulness more quickly than squirrels that did not hear bird calls after the hawk’s call.

Scientists say this suggests squirrels are able to tap into the casual chatter of many bird species as an indicator of safety.

The authors said: “We knew that squirrels eavesdropped on the alarm calls of some bird species, but we were excited to find that they also eavesdrop on non-alarm sounds that indicate the birds feel relatively safe.

“Perhaps in some circumstances, cues of safety could be as important as cues of danger.”

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