Friday, January 31, 2014

Surviving the Cold, Part 1: Birds

Brrrrrrr. The United States is experiences some extremely cold weather this winter. It is easy for humans to cope with cold weather. Outside? Layer up with thermals and jackets! Inside? Flip a little switch or build a fire and your home is mmmm toasty varm.

That is us. That is humans. Ingenuity is with us... well, most of us. How do other living things cope with the cold? That is the real question.

This is part one of multiple that look into adaptation and coping mechanisms plants and animals use to survive cold weather. Today, we are focusing on...


A curious Steller's jay looking for a free handout.
Photo by: Matt Brincka

The twit twittering of birds usually can be heard during the spring and summer months. Once falls comes around and cold weather sets in, the skies and trees become almost mute. When walking through a forest during the dead of winter the lack of sound is almost a surreal experience. You're enjoying the solitude, minding your own business, and all of a sudden you hear a sweet song followed by a raspy chatter. You spin your head around to see a flash of black and white moving from branch to branch. To your surprise, it is a teeny tiny chickadee, seemingly unharmed and not caring that the temperature is frigid, making all the noise.

Why are you here chickadee when all the other birds are gone? Where HAVE all the other birds gone?

Just like you and I, birds are warm blooded; they need to maintain a constant body temperature close to 106 degrees fahrenheit. If they don't maintain a relative constant body temperature, they risk extreme bodily harm and even death. To thwart death, birds have evolved multiple behaviors and adaptations that allow them to live in, or run away, from the cold.

The most well known form of birds adapting to cold weather is escape. Birds are one of the few species on earth that participate in long-distance migration. Now, not all birds migrate and not all bird migrate because of the cold. Winter typically brings a depleted food supply for all animals. Bird that rely of insects really need to scoot town when cold weather hits, because their food source also disappears or is severely depleted.

Surface Area Management
Many smaller birds have a few tricks to reduce their overall surface area, which helps reduce heat loss. On cold days, morning and evenings, you often find birds cuddled together on a branch or within a bush. This huddling not only reduced an individual bird's surface area exposed to the elements, but they are also able to share body heat! When there is no group to huddle with, some birds will fluff and puff up their feathers till they look like a little, fuzzy ball of joy, ultimately reducing their surface area to minimize heat loss.

It might not seem it to us, but dense foliage is a life saver (literally) for many bird. Sparrows, chickadees, and even larger birds like jays and owls will search for cavities in trees, dense bushes, or even a covered porch. These shelters keeps the elements at bay, or at least make them more tolerable. Staying out of the cold wind, freezing rain and snow is a good first line of defense when trying to keep warm.

A house finch seeking shelter on our covered porch
during the Colorado floods (cellphone picture).
Photo by: Matt Brincka

Birds also fatten up for the winter... just like us humans! Fat is both a great insulator and energy source. In some species, fat can make up over a tenth of a bird's winter body weight. To keep the pounds on, birds need to eat a lot of fatty foods. Make sure you keep on reading to find out how you can help!

Body Circulation
Ever see a gull or goose standing on a frozen lake or pond? Ever say to yourself "geez, how can they stand the cold?" Surprisingly enough, that is a winter weather adaptation as well! Some bird species will actually regulate their body circulation, keeping the nice, warm blood circulating near their vial organs and allowing their extremities to cool down.

Do you shiver in the cold? I know I do. When humans shiver, all of our joints, skin, muscles and fat jiggle and contract to help generate heat. Some birds, like chickadees, go through a similar process that doesn't involved the intense shaking humans experience. Birds will actually contract opposing muscle group to generate and retain heat.

Regulated Hypothermia
As you've noticed, most of the above survival techniques involve ways to keep warm. Keeping warm in the bright sunshine is one thing, but what do birds do when the lights go out and the temperatures plummet at night? Some birds go through a process called called regulated hypothermia, where they drop their body temperature as much as 20 degrees Fahrenheit from their sunshine/daylight temperature. This decrease in body temperature allows birds to lower their metabolism, meaning they consume less energy while sleeping.

A grey jay soaking in the sunshine on a bright winter day.
Photo by: Matt Brincka

How can we help?

  1. Provide your feathered friends ample amount of fatty, high energy foods, such as black oil sunflower seeds, safflower seeds, fine meat scraps, peanut butter, mealworms, and suet (fat). You can buy pre-made suet feeders with seeds and nuts worked in, or you can go to your local butcher and ask for their leftover suet. They'll gladly give it to your for pennies, if not free.
  2. When weather gets particularly bad, put out 1-2 extra feeders. The increase in food supply will help birds spend less energy forging.
  3. Mark sure seed is dry and accessible. Instead of putting out open seed troughs, think about using hopper or tube feeders. Also, removing snow from platform feeds and clearing an area on the ground by your feeder to spread seed will help keep the food dry.
  4. Making a windbreak by your feeders will help with the cold wind. You can do this most effectively by planting bushes and trees. If you can't do that, using this year's christmas tree or a make-shift snow fence will do wonders.
  5. If you're having problems with your bird bath freezing, you can 1) use a water heater/heated dog bowl or 2) if there is snow on the ground, don't worry about it! Birds will use snow for a water source! Warning: be careful when using a heater to warm a bird bath. On extremely cold days, water is known to freeze on a bird's feathers, which can be fatal. Instead of leaving a large, open bird bath... put raised surfaces such as wood and rocks so birds can access it for water to drink, but won't be tempted to bath.

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