Winter is a Challenging Time for Birds
Winter poses several challenges for birds. Wildlife photographer and naturalist Stan Tekiela talks about the hardships our feathered friends encounter.
Scarce food supplies and limited water are just a few obvious challenges to winter survival for nearly all birds.
Extremely cold temperatures, strong winds, driving snow, and freezing rain are another set of problems that birds must overcome. Add to this the fact that long and dark nights can be deadly for birds. So just how do birds survive the rigors of winter?
As you can imagine, birds have many adaptations to help them survive in extreme winter weather. One of these adaptations is more common than you think. Feathers are the first and best line of defense and are critical to a bird’s survival. But what do you really know about a bird’s feathers?
Many of our wintering birds, such as the American Goldfinch and Black-capped Chickadee, add additional feathers in preparation for winter. A goldfinch or chickadee is covered with approximately 1,100 feathers during summer; that number increases to more than 2,500 in winter—about a 45% increase in feather density.
However, if you look at the bird, it really doesn’t look like it has so many more feathers. That is because the outer contour feathers overlap each other and lay flat. The other increase in feathers are in small, fluffy down feathers, which occur under the outer feathers, so you won’t see them at all.
Not only do birds that live in cold climates have more feathers than birds in warm climates, but aquatic birds, such as ducks and geese, also have more feathers than terrestrial species of a similar size. This is undoubtably due to the rapid loss of heat when a bird is exposed to water.
To demonstrate just how important feathers are for birds, all you need to do is look at how much feathers weigh. This might be a little confusing at first, but listen to this. For a bird to fly, it needs to be as lightweight as possible. So nearly every part of a bird’s body is modified to make it light. For example, birds don’t have teeth because a full set of teeth is very heavy. Instead, they have a lightweight bill or beak. Birds also have mostly hollow bones as opposed to solid bones, which are extremely heavy. So…feathers need to be light. Who hasn’t heard of the saying “light as a feather?” Individual feathers are light, but when you put all the feathers together, they have considerable weight. In fact, in most bird species, the feathers are usually two to three times heavier than the bird’s entire skeletal system.
Obviously, feathers keep the birds warm. During very cold days and nights, birds fluff up their feathers, reducing the amount of heat loss by up to 30% compared to when their feathers are not fluffed up.
Bird feathers also help keep birds dry in wet weather. We have always thought that birds express oil from a gland near the base of their tail, called the urpygial gland, to make their feathers waterproof. Turns out this isn’t totally correct. While the oil might help with water repellent, it’s not essential. The microstructure of the feathers’ barbs and barbules provides evenly spaced ridges with narrow gaps that shed water quickly and efficiently, giving the feathers the waterproofness without the oil. The oil is there to keep the feather lubricated and from becoming brittle and breaking prematurely. As you can see, there is more to a bird’s feather than meets the eye.
You can follow Stan on Facebook and Twitter, or contact him via his web page. Stan’s nationally syndicated NatureSmart Column appears in more than 25 cities spanning 5 states (Minnesota, Wisconsin, Michigan, Illinois, and Pennsylvania) and is circulated to more than 750,000 readers.
If you enjoyed Stan’s post, consider one of his amazing nature books: Wild Birds, Bird Trivia, or Backyard Birds: Welcomed Guests at our Gardens and Feeders.
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