Birds keep close track of seed business.

Your little chickadee might just make the perfect accountant. These tiny birds keep such a close eye on their food supplies that they know how many seeds are missing and replace almost every one, new research suggests.

Chickadees retain very little body fat, so they have become adept at managing caches of food. A single chickadee hides one or two seeds in hundreds of spots over several acres.

Experiments had shown that when the birds grow fatter, they tend to store fewer seeds, says Jeffrey R. Lucas of Purdue University in West Lafayette, Ind. He and his colleagues suspected that the birds might compensate for a decrease in the availability of seeds by retaining extra body fat.

Carolina chickadees in the laboratory did not put on extra weight when the scientists pilfered their seed caches, however. In the winter, the birds replaced the missing seeds and doubled the amount of time they spent finding, storing, and checking on their food supplies, Lucas says.

In the summer, even though food supplies and temperature in the lab did not change, the birds failed to compensate for lost seeds. This fits with earlier studies by the group indicating that the birds' yearly rhythms regulate seed storage.