One of the annual traditions at the Kansas Wetlands Education Center is the Audubon Christmas Bird Count. It may seem odd to count birds in the middle of winter, but it’s actually a great way to keep track of species and population trends. A week before Christmas, this year’s count was bitterly cold. The high that day barely squeaked above freezing and most of the day hovered in the teens. Much of the water around Cheyenne Bottoms was frozen over, and everything was covered in an inch or so of snow. You’d think that every bird in its right mind would be high tailing it south, or at least hiding someplace warm and cozy, right?
In fact, birds are tougher than most of us think. While the human birdwatchers huddled in our trucks with heaters roaring, we found thousands of birds going about their daily lives as if they didn’t even notice the cold. As I watched, I was amazed at the different ways birds are built to deal with winter temperatures and weather.
Some of the first birds that we saw on our count were ducks and geese – swimming in the frigid waters of an old sand pit. The edges of the sand pit were lined with ice, and here were hundreds of birds cheerfully paddling around. How do they do it? Water that cold would be dangerous for a human in as little as 10-20 minutes, let alone for days at a time.
Birds that spend a lot of time in very cold water have a few tricks up their sleeves. They have a special system of blood flow in their legs called “counter current heat exchange.” If that sounds more like something to do with your furnace than a bird, the principles are actually very similar! Heat moves from warm areas to cold areas, and both your home furnace and some bird species take advantage of that. In birds, the veins and arteries in their legs are very close together and almost intertwined. This means that the warm blood coming from the bird’s body passes close enough to the cold blood leaving the legs to warm it up before it enters the body. The warmed up blood goes into the body, and the cooled down blood goes into the feet and legs. Their feet stay just warm enough not to freeze, and they lose very little heat to the cold water.
Their feathers are another great way for birds to stay warm. Anyone who has ever owned a down jacket or comforter knows just how warm bird feathers can be. For birds like ducks and geese, their feathers are waterproof as well as insulating. They can float in the coldest of water without ever having it touch their skin. Birds that avoid the water take advantage of their warm feathers too, fluffing them up to trap as much warm air as possible. This not only keeps them warm, but has the entertaining side effect of making them look as round as little beach balls. The bluebirds, meadowlarks, and even birds of prey that we saw on our bird count were all as puffy as could be as they sat on fences, nestled into tree branches, or perched on power lines.
Watching birds on a cold day is a reminder of the wonderful variety of animals all around us. Animals not only survive conditions that would make us humans miserable (or even kill us!) but they thrive! They’ve got tools and strategies that we don’t, and it’s fun to look around Cheyenne Bottoms and appreciate the diversity here. As for me, it was even more fun to finish our counting, go inside the nice warm KWEC and enjoy a good hot meal – that cold day was for the birds!