Get Wild: Getting to know Summit’s winter birds
Nestled deep in the snow, a white-feathered bird rests camouflaged and warm. Hidden from predators — such as coyotes, foxes and weasels — and foiling the efforts of the best birdwatchers to find them, Colorado’s white-tailed ptarmigan is an iconic species of sub-Alpine and Alpine habitats in the High Country.
Surviving our winters is no easy task, and many birds escape the season by moving south or to lower elevations where food and other resources are more readily available. Those that stay, however, must be well-adapted to persist in low temperatures and cold winds.
Ptarmigan are armed with more than snowy-colored feathers in winter. They sport feathers on their nose, or nares. These feathers prevent the small openings from freezing and offer a barrier, warming the air before it enters the lungs. And feathers on the eyelids and feet protect this small grouse from cold snow.
If you don’t have the opportunity to go high in winter, there are many other birds that remain behind in our forests. Keep a close eye on aspen trees for small holes or cavities. Excavated by woodpeckers, these cavities are also used by other birds, such as wrens and swallows, as summer nest sites.
In winter, however, they become a refuge from frigid air with temperatures warmer inside by as much as 27 degrees. Mountain and black-capped chickadees are some of the birds that take advantage of these cavities during cold periods, allowing them to conserve the energy they need to forage for food outside.
Speaking of chickadees, these familiar species are a favorite source of art, and the image of a plump bird on a branch is common. This plump appearance in winter has an important function. The fluffed-out feathers that give the bird a cute, chubby look actually create more insulation around the body, maintaining heat.
Unlike ptarmigan, chickadees and most other birds don’t have feathered legs and feet, leaving them exposed to the temperatures. A beneficial mechanism called counter-current exchange protects their feet from freezing. As blood flows from a bird’s arteries to its feet, some of the warmth is passed to the veins, which are returning blood to the heart. Ultimately, the bird’s feet can remain at temperatures above freezing, which benefits a perching chickadee, and enables ducks and gulls to stand on ice for long periods without damage.
One of my favorite birds, the American dipper, is known as the only aquatic songbird. At first glance, this chunky, short-tailed, grayish bird seems dull. Don’t let looks deceive you, however. It has some unique adaptations that should give it superhero status. Not only can American dippers survive foraging for small fish, insect larvae and other invertebrates in the near-freezing waters of the Blue River, for example, but they can also withstand temperatures as low as minus 22.
Their dense feathering, which far exceeds that of other birds their size, helps them maintain their body temperature. In fact, dippers prefer the cold and have low tolerance for higher temperatures. At 97 degrees, they probably can’t survive.
While many bird species leave Colorado’s mountain communities during the winter, those that can find sufficient food stay behind. Winter bird-watching offers an ideal opportunity to get to know them and help them make it through the winter with some simple actions:
Cleaning your bird feeders helps stop the spread of diseases. Birds don’t see windows and often collide with them. Closing your blinds eliminates the reflection of trees or the appearance of a pathway, preventing birds from attempting to fly to or through a pane of glass.
“Get Wild” publishes on Fridays in the Summit Daily News. Susan Bonfield is the director of Environment for the Americas, a nonprofit organization that coordinates World Migratory Bird Day, the global celebration of migratory birds.
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