The weather outside is frightful,
but the birds are so delightful!
Although many of our bird species have 'flown the coop' for warmer climes, we still have many that make their home here at River Bend year-round. You may have noticed one of their not-so-subtle adaptations... like the kid in the puffy jacket on A Christmas Story, our winter residents spend time putting on weight in the fall, growing warm down plumage, and puffing out their feathers to keep warm. Staying in the north affords several advantages to these birds--they avoid the risks of migration and maintain their territory, unlike exhausted migrants who must compete for nesting sites upon their return in the spring.
Some birds, such as the black-capped chickadee, are very good at adapting to the cold, especially at night when temperatures drop dramatically. They perform a nifty little trick called regulated hypothermia to save valuable energy and stay warm. Similar to torpor, or full hibernation, this allows birds to decrease their body temperatures by as much as 22 degrees in the evenings without expending much energy waking in the morning as temperatures warm. Conversely, Hummingbirds who experience torpor expend a lot of energy each time they emerge from their deep sleep, which is why this strategy is so uncommon in non-migratory, cold-climate species.
This tiny cold-weather expert has yet another trick up its plumage... shivering. Shivering is our body's attempt to produce heat and keep the core warm. While these little birds do not shiver in the same sense that we do, muscle contractions produced by firing opposing muscle groups generate enough heat to help keep this little bird warm.
Many species depend on a mixture of these adaptations to keep warm during the winter. Dense pines and the act of huddling with other birds helps maintain a constant body temperature, while fatty foods found at nearby feeders, such as sunflower seeds and suet, aid in maintaining additional insulation. Some birds are masters at redirecting their circulation to keep different parts of their bodies warm. Gulls, for example, will circulate blood to vital organs while allowing their extremities to drop to near-freezing temperatures, (Audubon.org). This allows gulls and other species to stand on ice for extended periods of time without freezing.
While most birds are leaving Wisconsin's wintery landscape, others are just arriving. This is a great time to search for young Snowy Owls as they perch on posts and poles scanning the ground below for prey. Interested in spotting other species here for the long-haul? Check out our new pocket checklist for River Bend's birds, available for free in the lobby! Really want to get your birding game on? Participate in this year's Christmas Bird Count through the National Audubon Society found at the link below.
As you know, birds play an integral role in every ecosystem on the planet and it's our responsibility to maintain their link in the web. Whether you provide food, promote dense foliage, or maintain heated birdbaths, please continue your efforts to help these amazing birds survive the brutal Wisconsin winters!
https://www.audubon.org/conservation/science/christmas-bird-count
Happy birding!
-CT
