Here is the latest For the Birds column, which runs weekly in several New England newspapers.
Despite the welcomed warm weekend, it had been a pretty rough past few weeks weather-wise. Snow, sleet, cold temperatures … in other words, a New England winter.
Most people survive winter by not venturing outdoors and, if it’s necessary to go out, limiting their exposure to the elements to short walks to and from the car. Those who do venture out into the snow, for fun or work, bundle up in apparel scientifically designed to battle the cold.
Birds don’t have the luxury of going inside and turning up the heat. Yet they have survived for eons the worst elements New England can throw at them. It’s nothing short of spectacular when you think about how they do it.
First of all, the ones that are not designed to survive a New England winter hightail it out of the region in the fall. They know what’s coming and head for warmer climes.
That alone is fascinating to think about. Some birds survive by fleeing the cold, some birds survive by toughing it out. Each strategy has its risks and rewards. The birds know which one works best for them.
Unfortunately, some birds that do stick around to battle the elements like true New Englanders will perish during the winter. This is particularly true of individual birds of a species that typically heads south for the winter. Most great blue herons and black-crowned night herons move south for the winter. Some stick around New England and brave the cold. If a winter is too harsh and the bird can’t find enough food, some of those birds will perish.
The same is true of Carolina wrens. They are relatively new to New England, having slowly expanded their range northward, and a harsh winter can take a toll on the population of the handsome little birds.
But, by and large, birds survive these harsh winters just fine.
I was surprised, however, to not see a single Carolina wren last week as I watched the snow falling. Usually one or two show up at my feeders and entertain me during a storm.
Most birds survive the cold nights by seeking shelter to stay out of the elements. I remember a few winters ago seeing a small bird fly under my neighbor’s awning. My curiosity got the better of me, and I had to check under the awning to see if the bird had found a comfy spot. Sure enough, I found a black-capped chickadee tucked into an impossibly small crevice in the corner of the awning. I saw the bird the next evening take the same route under awning.
Birds will also seek shelter in birdhouses during the winter. That’s why it is important to clean out your birdhouses in late summer or fall so you can offer a clean escape from the harsh overnight temperatures. Some birds will huddle together for extra warmth.
A bird’s greatest defense against the cold is its feathers. Some birds grow extra feathers for the winter. Birds also “fluff” or “puff out” their feathers to trap warm air closer to their bodies. The down feathers, found underneath the colorful external feathers, are particularly effective in protecting birds against the cold. Birds will even shiver — similar to humans — for extra warmth. The feathers are also insulated by natural oils.
Some birds enter a state of torpor or hypothermia, whereby they drop their body temperature and remain still to conserve energy. They are vulnerable to predators during these states, but that risk beats freezing to death.
Birds’ legs and feet may seem dangerously exposed, but unlike our hands without gloves or feet without boots, they are covered with scales to help retain heat. They can also regulate the amount of blood flow to their legs separately, which helps to keep other parts warmer. That can help explain why birds sometimes stand on one leg and tuck the other one into its feathers.
Perhaps the most important thing a bird can do to keep warm during winter is eat. Natural foods remain in the wild — such as robins and waxwings eating berries — but certainly backyard birdfeeders help them survive, too. Sunflower seeds and suet are high in energy, which helps keep the birds fueled in order to survive cold temperatures.
Finally, I always found it interesting that some birds will bury themselves in snow to keep warm. Once it’s settled on the ground, snow is a great insulator. Just ask the next ruffed grouse you see.