How Do Birds Survive Winter?
I know autumn has arrived in New York when I begin to see flocks of Canada Geese fly over head in their classic V-formation, headed south for the winter. While Canada Geese have a short migration, some species travel thousands of miles. Arctic Terns fly nearly 25,000 miles to their wintering grounds!
If you are ever envious of the birds that get to escape the harsh cold by heading south, remember that not all species migrate. In fact, many species stay in the same place year round and tough out the cold using other techniques. You may notice Black-capped Chickadees are frequent flyers at your bird feeders during the fall. While it may seem like these tiny birds have huge appetites, much of the seed is actually being stored in cracks of tree bark or even between splinters of wood on the siding of your house. Unlike bird species you might see in your yard in late spring and summer, the chickadee is one species that does not make the seasonal flight to warmer climates. Instead, they prepare as much as they can during the fall to survive outside in the cold throughout the winter.
So if you can’t even remember where you put your keys, how is a tiny bird (about 10 grams!) going to remember where they put all that seed from your feeder? Chickadees can actually grow and shrink their brains! When it’s time to store food in the fall, the birds need a strong mechanism for remembering their hiding spots. Neurons are added to the hippocampus region of their brain, increasing volume by about 30%. As the winter comes to a close, temperatures rise, and food becomes more readily available, their brains shrink down because the birds no longer need the super-strong memory.
Another bird species, the Golden-crowned Kinglet, also braves the bitter cold winters of the Northeast. Unlike the Black-capped Chickadee, you will never see the kinglets at your seed-filled feeders because they only eat insects. But when was the last time you saw an insect flying around in the middle of a January snowstorm? How can the kinglets survive the winter if there is no food supply? These tiny birds (even smaller than the chickadee!) search for moth-caterpillars that spend the winter on trees. At night the birds huddle in groups, puffing their feathers to an inch thick and tucking their heads to conserve heat.
While a steady food supply is important during the cold winter months, the birds also need to conserve their energy and heat. Small birds like chickadees and kinglets can drop their body temperatures by up to 15 degrees F at night with an adaptation called “regulated hypothermia.” This technique enables them to save nearly a quarter of the energy they use each hour.
So the next time you are feeling jealous of the species that get to flee the cold Northern winters, remember that you are not the only one who has to face the cold. Think like a chickadee or kinglet, eat lots of snacks, puff up in jackets, huddle with your friends and family for warmth, or just sleep a little colder at night!
- You can help birds by putting up a feeder and monitoring winter birds through Project FeederWatch.
- Provide winder shelter for birds by providing a brush pile or winterize your nestboxes and make them roosting shelters for birds.