Every so often “a new study will come out about Eastern gray squirrels,” he noted, “that will tell us something about their intelligence or behavior patterns that we should have figured out a long time ago.”

A few years ago there was the revelation that squirrels “lie,” fake-burying nuts when other squirrels are watching. Last year researchers determined that squirrels engage in “spatial chunking,” sorting nuts by size, type and possibly nutritional value.

“There’s not a lot of squirrel data out there,” Mr. Allen, 49, said. “So the first step is collecting the squirrel data. You start to see patterns in behavior, and then you can use the data for any research you’re working on.”

The data from the census in Atlanta was used by a wildlife epidemiologist for a paper on the spread of West Nile virus in a different park in that city.

Another reason for the count is to simply answer the question “How many squirrels are in Central Park?”