Keith A. Tarvin is not repeating the philosopher’s mistake. He’s a biologist at Oberlin who studies what kind of information animals derive from the many sounds around them. He and his students set out to get some hard data on what squirrels listen to.

[Like the Science Times page on Facebook. | Sign up for the Science Times newsletter.]

“I’ve been interested in alarm calls for a while,” he said. In a recent scientific paper, for instance, he reported that gray squirrels pay special attention to the alarm calls of robins. This kind of eavesdropping is widespread in nature. “Even some lizards that don’t make their own vocal sounds eavesdrop on some other animals like birds,” he said.

As he and his students discussed the soundscape squirrels live in, he said, “that led us into chatter,” the general background noise of nature — in particular the calls that birds make when nothing big is going on. Their question was not what one sparrow might be saying to another, but whether squirrels took note of the birds’ conversations when they weren’t shouting about hawks.

The researchers hypothesized that the squirrels were paying attention, and over the course of a couple of years Dr. Tarvin and two undergraduates, Marie Lilly and Emma Lucore , designed and conducted an experiment to test that idea. They played a recorded screech of a red-tailed hawk, which put the squirrels on alert and caused them to act vigilant.

Then they played recordings of desultory bird chatter, or of background noise without birds. They made all the recordings at one bird feeder at different times. Then Ms. Lilly, who did the field work (Ms. Lucore had graduated after helping to design of the experiment), had to find squirrels around Oberlin, in the winter, on her bicycle. It was cold, she said, but squirrels are easier to observe in the winter, with no leaves to obscure their actions.