"Try to remember the kind of September when life was slow and oh, so mellow."
Those lyrics, from the musical "The Fantasticks," certainly do not describe chickadees.
September is anything but slow for these little birds. They're scatter-hoarding, feverishly gathering and hiding thousands of individual seeds—and a few insects—in cracks and crevices beneath tree bark, among lichens and probably in a few really good hiding places known only to them.
But the second verse of the song— "Deep in December, it's nice to remember, Although you know the snow will follow"—captures one of the most remarkable survival adaptations in the natural world.
Once December comes, it's nice to remember—and they do.
Chickadees can remember the locations of thousands of food caches, and they can distinguish their own hidden seeds from those stored by other birds.
They're able to do this because their brains are remarkably adaptable.
Beginning in early fall, the part of the brain responsible for spatial memory expands as chickadees produce an unusually large number of new neurons while they're creating and memorizing hundreds—indeed, thousands—of cache sites.
Then, when the snow follows, that enhanced spatial memory helps them recover the food they tucked away months before, allowing them to survive even the harshest winter weather.
As spring arrives and food becomes plentiful again, the need for extraordinary spatial memory declines. Many of those extra neurons are pruned away, and by the breeding season, that memory center has returned to its usual size.
Deep in December, it would be nice to remember-- where I put my phone—or my keys. Humans, even older adults, can still produce new neurons in parts of the brain involved in spatial memory, although nowhere near on the spectacular seasonal scale of a chickadee.
And I am not a chickadee.
