For the Birds Radio Program: Winter Solstice

Original Air Date: Dec. 21, 1994

Winter begins tomorrow according to astronomers, but birds and sensible humans know it really started last month. (4:11) (Date confirmed)

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The winter solstice takes place tomorrow. The solstice is the moment in time when the sun is exactly over the Tropic of Capricorn, reaching the most southerly point in the earth’s sky. That also makes tomorrow the shortest day of the year in the northern hemisphere, and tomorrow night the longest—what Robert Frost referred to as “the darkest evening of the year.”

So astronomically speaking, it should be smooth sailing after this. The days will be getting longer and the sun climbing steadily in the sky. But let’s face it: astronomers have their heads in the clouds. People grounded right here on earth know darn well that this year, winter hit the Sunday after Thanksgiving when the blizzard struck, and will get a lot worse in January and February. Over the long haul, earth’s temperature obviously depends on a star 93 million miles away, but from week to week, it’s more noticeably affected by streams of air moving from one area to another right down here, and the worst winter weather blasts from the arctic kick in in January and February.

The hardships of winter for birds aren’t limited to the cold. As a matter of fact, unless the mercury drops to an unusual extreme for the upper Midwest, cold temperatures are fairly inconsequential for birds. As long as they have enough food to keep their metabolic furnace burning, birds can live through the worst weather imaginable. The trick is in finding food enough during the short day to sustain them during the long night in a season when plant and insect food resources are at their lowest levels of the year.

Northern finches remain in the northland simply because they’re adapted to eating the seeds from pine and spruce cones. This food fortuitously grows on the highest branches of tall trees, and can’t be buried under mountains of snow. Chickadees, nuthatches, and woodpeckers need insect protein year-round, but are adapted to probing into the bark of trees for buried treasure: frozen insects eggs and pupae hiding out in hopes of actually seeing spring. Fortunately, there are always plenty more where they came from, so overall there’s no shortage of chickadees and no shortage of insects.

Owls eat warm-blooded food, but jumping mice and chipmunks hibernate, and voles and non-hibernating species of mice hide out under snow. Owls have thick feathering on their bellies and feet partly for insulation against cold, and partly to protect their bodies from shards of ice as they dive into snow for a meal.

Throughout the season, as astronomers note the ever-increasing day length and the steadily warming temperatures, the season will actually grow harsher for birds. The easiest food sources quickly become depleted, and some food supplies will actually run out. As birds wander about searching up new food sources, their unfamiliarity with new areas makes them vulnerable to predators and other dangers of the unknown. Soft, fluffy snow that falls during deep-freezes eventually melts a bit, and then refreezes, becoming impenetrable for all but the strongest owls, and sometimes even entombing hiding Snow Buntings or grouse beneath.

There are always many survivors of winter. Birds are adapted to the conditions in which they live, and so perhaps it’s no miracle that come spring there are plenty of birds remaining. No, the miracle isn’t that birds survive the winter, but that they never lose their interest in living. They keep that intense vivacity that brings us bundled and sluggish star gazers joy and pleasure, and keeps our own heart flames blazing through the worst that winter throws our way.