For chickadees, memory is a product of natural selection

[Cara J]

On the mountaintops of the Sierra Nevadas, mountain chickadees (Poecile gambeli) create food caches to survive the winter, and they rely on their memories to find them. Researchers had already known that in places of higher elevation or with harsher winters, chickadees often rely more on these caches. In previous research, they found that chickadees in these areas had a larger hippocampus, a part of the brain that helps with memory, and they had more neurons in their hippocampus than other chickadees. Recently, biologists found these traits relating to good memory are gained through natural selection. In the study published in Current Biology, they used passive integrative transponder tags and feeders equipped with radio frequency identification devices. The tagged birds were assigned to one of eight feeders. When they attempted to get food from a feeder that they weren’t assigned to, the machine recorded it but no food came out. “Any time a bird lands, it records the time and ID of every bird,” said Vladimir Pravosudov,biology professor at the University of Nevada, Reno, and the study’s corresponding author. The team recorded how long it took for the birds to learn which feeder gave them food and how well they remembered [...]

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