Squirrels listen in on bird communications to learn when predators have left the area and it is safe to stop being on high alert, according to a new scientific study.
Grey squirrels eavesdrop on the chatter between nearby songbirds as a sign of safety. Birds chatter when they feel safe to communicate the absence of danger or share their location. This “chatter” from multiple bird species could therefore be a useful cue to other creatures that there is no imminent threat.
Researchers observed the behavior of 54 wild Eastern gray squirrels (Sciurus carolinensis) in public parks and residential areas in Ohio in response to threat, which they simulated by playing back a recording of the call of a red-tailed hawk (Buteo jamaicensis), a common predator of both squirrels and small birds. They followed the predator’s call with a playback of either multi-species songbird bird chatter or ambient sounds lacking bird calls and monitored the behavior of each squirrel for 3 minutes.
The researchers found that all squirrels showed an increase in predator vigilance behaviors, such as freezing, looking up, or fleeing, after they heard the hawk’s call. However, squirrels that were played bird chatter afterwards performed fewer vigilance behaviors and returned to normal levels of watchfulness more quickly than squirrels that did not hear bird calls after the hawk’s call. This suggests that the squirrels are able to tap into the casual chatter of many bird species as an indicator of safety, allowing them to quickly return to getting on with normal behaviors like foraging rather than remaining on high alert after a threat has passed.
Journal Reference: Marie V. Lilly, Emma C. Lucore, Keith A. Tarvin. Eavesdropping grey squirrels infer safety from bird chatter. PLOS ONE, 2019; 14 (9): e0221279 DOI: 10.1371/journal.pone.0221279