How does a bird that only weighs one-third of an ounce survive the Wisconsin winter? Where do turkeys find food if the ground is covered in two feet of snow? Is migrating to Central America as easy as jumping on plane and taking a nap? A group of more than forty excited birders set out from the Visitor Center this Sunday to answer these and other questions about the lifestyles of our avian friends in the winter.
Fortunately for us, the bright sun and temperatures in the thirties warmed us as we crunched over hard snow during our journey through Longenecker Gardens. Right away a blue jay flashed its sapphire feathers through the trees from left to right. A rambling song drew us west and we watched as house finches looked for seeds in the crabapples and a few black-capped chickadees searched along the outer branches. Nearby turkey tracks revealed the large birds’ recent food choices. As other sources dwindle, turkeys turn to the crabapples for late winter sustenance, clumsily flying up into the small trees and doubling over the branches to reach for the apples. A graceful bird, they are typically not.
Across the road and down along the Wingra Woods trail we watched for woodpeckers in the old oaks. American crows squawked on their way to somewhere while a red-bellied woodpecker chirped as it examined nooks and crannies in the high branches for insects to eat. There are four typical winter woodpeckers at the Arboretum and from smallest to largest they are downy, hairy, red-bellied, and pileated woodpeckers. Downies are very small and trim, with a tiny beak. Like downies, hairy woodpeckers are also black with white bars in back with an all white front. However, hairies are almost twice as stout, 9 inches long as opposed to 6, with a beak that is as wide as its head, about 1 inch long.
Red-bellied woodpeckers have a distinctive red cap and nape, with a small pink splotch in the belly feathers. Finally, the pileated woodpecker measures a whopping 16 inches long, with an all-black back, giant bill, and flaming red crest. All four of our winter woodpeckers are busy excavating rotting wood in search of insects and have recently begun their drumming calls for mating season.
Stopping by Big Spring, we discussed the ingenious ways that Wisconsin birds survive large snowstorms, reduced food sources, and subzero cold snaps. Take the black-capped chickadee: one of our smallest songbirds, at just 11 grams, the chickadee must eat three times its body weight during the winter months to put on enough fat each day to last through the long dark nights. Seeds from neighborhood birdfeeders are certainly helpful, while other chickadees scour twigs for insect larvae and any small leftover seeds from the growing season. Their bellies are white with short fuzzy down feathers, which they fluff up in heavy winds to trap even more body heat against their skin. Chickadee beaks and feet are unfeathered, and these they are able to drop to just above freezing temperatures and still be functional. Another trick the birds employ is to go into a short-term hypothermia on the coldest nights. They will reduce their core temperatures by up to 20 degrees Fahrenheit and shiver constantly for 8 hours while waiting out a major cold snap. They may also hide out in tree cavities to escape the wind. One effective strategy that chickadees and other birds seem to dislike is snuggling. Maybe stoicism at all costs is written into the chickadee gene code.
Our group decided to venture out to Skunk Cabbage Bridge to see the first plants of spring and we were also rewarded with sights of several soaring raptors overhead. First, a sharp-shinned hawk quickly flapped to the northeast at a medium height. Several red-tailed hawks followed, soaring up into the warm air vents, or thermals, rising due to the sun’s warming of the earth. Finally, three bald eagles, including one immature bird with mottled black-and-white feathers and a brown head, took turns playing on the breeze hundreds of feet up. Those of us with binoculars wondered with awe and talked about which large bodies of water these eagles may be headed from and toward. We also saw the skunk cabbage, already up a few inches out of the mud.
Our final species of the afternoon was the honking white-breasted nuthatch, which we spotted during our return journey to the Visitor Center. This gave us twelve species for the day overall, a strong showing for a group of forty-five on a sunny warm afternoon. With spring migration coming in the near weeks, it was a nice warm up to the serious birding season that will begin soon.