This is bird note.

As the colder months arrive, birds that remain in northern climates face the harsh realities of staying warm and finding food.

Some birds approach the food problem by storing it in advance, in a behavior called caching.

Chickadees, nut hatches, jays, and some woodpeckers are known to

cash large supplies of mostly seeds in a great many places. Scatter hoarding, it's called,

a kind of adaptive specialization that requires very good spatial memory. So what enables the birds to find the seeds they've stored?

Scientists have shown that black-capped chickadees amplify their spatial memory in early fall

by actually adding brain cells to the hippocampus, the part of the brain that supports spatial

memory. Taking the question a step further,

another study examined how severity of climate

might affect the brain power of different populations of chickadees.

These researchers found that where a stash of winter food is critical,

say in harsher northern climates.

Black-capped chickadees had a substantially larger hippocampus size

and more neurons in this part of the brain

than those birds from more mild southern regions.

In other words, when the living is easy,

having a big brain isn't such a big deal.

For Bird Note, I'm Michael Stein.