Squirrels are clever creatures. They eavesdrop on the sounds of the songbirds melody, to work out whether they are still in danger or if the coast is clear. This allows them to come out from their hiding spot, a study has found. Some animals are known to tune in to cries of alarm from other creatures with which they co-exist to assess danger and squirrels are now known to be one of those animals.
Professor Keith Tarvin, co-author of the study from Oberlin College, Ohio, and his colleagues reported in the journal PLOS ONE how they made their discovery. The team studied the behavior of 54 wild eastern gray squirrels (Sciurus carolinensis) located in parks and residential regions in Ohio. They simulated “threats” to these animals by playing them 1-3 second recordings of a red-tailed hawk (Buteo jamaicensis), a bird of prey that typically hunts squirrels and small birds alike.
These “threats” were followed by 30 seconds of silence before a second recording was played. The researchers had two recorded follow-ups to the predator call. One recording contained a multi-species songbird “chatter” and the other was an ambient sound without any bird calls. The team played these three minutes after the first recording while monitoring the squirrels’ behavior during this time.
All the squirrels being monitored that heard no bird chatter followed by the threat showed more predator vigilance behavior by either fleeing, freezing, or looking bewildered. This is no surprise, because to the squirrels’ point of view, a red-tailed hawk was about to kill them. Meanwhile, all those that heard the recording with the chattering birds exhibited less of these behaviors and quickly returned to a normal level of vigilance.
The authors explained:
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.
Furthermore, the team suggested that since the amount of human-made noise is increasing, squirrels may have a more difficult time to eavesdrop on birds, which means they will most likely have to spend more time being alert and stressed out than foraging around.
Perhaps the impact of human activities on natural soundscapes may compromise the survival of wildlife. What do you think?
