January 2018 Wildlife Watch by Marian Harman

White-throated Sparrow by Doug Pederson

On those frigid days of winter when the wind is high and the temperatures plunge below zero on some nights, I’m sure you feel as sorry for the birds as I do. How do they stay warm in winter? It seems something of a miracle when we see them at our feeders in the morning. The simple answer is that its not at all easy for them, and not every bird will survive sub-zero nighttime temperatures. But, birds do have a range of adaptations and strategies to help them.

Most important to warmth is feathers, which are specially adapted to trap warm air. On cold days, we see birds that look as fluffy and round as a little kid dressed up in a down jacket. When fluffed up, those feathers trap a lot of warm air between them. And by regularly preening and applying oil from the oil gland at the top of their tail, they can keep those feathers completely waterproof.

Another physiological adaptation is that birds can keep their core temperatures up by circulating warm blood around internal organs, while diverting it from less important peripheral areas. Legs have insulating scales covering them, and if the legs get too cold, birds can tuck one leg up at a time into their feathers and stand on only one leg. Waterfowl have a  special type of circulation in their legs in feet. Veins and arteries are located very close to each other in the leg, so warm blood heats up colder blood.

Many birds will shiver throughout a cold night ¬†read more…