For the Birds Radio Program: Leap Year Day
Leap Year Day is an appropriate time to consider how birds don’t need a watch or calendar.
(Recording of an Eastern Bluebird)
Today is Leap Year Day–the day when we reset our watches and digital clocks to readjust our human calendar to the solar calendar by which birds live out all their days. It’s a satisfying thought for me that at least once every four years all of us–including those who never lay on their backs on summer nights gazing up at the stars–are forced out of our little world of man long enough to adjust our schedules to a higher universal order.
You’ll never see a bird with a Rolex. For many people, birds represent absolute freedom–from responsibilities, worries, and, perhaps most of all, schedules. These people never seem to think about how much responsibility is involved in taking care of a nestful of helpless hatchlings, and if birds don’t worry, it’s only because they’re so busy escaping from danger that they don’t have time to indulge in worries. And the universal time clock by which a bird’s life is regulated is a far stricter taskmaster than the most relentless beeper.
The clocks of some birds are set by the weather. Robins and Canada Geese start moving north from their southernmost wintering grounds as early as late January–though they never stray beyond the 37 degree isotherm. As cold fronts move the warmth south, these species are allowed to retreat, at least temporarily. But many of the later migrant species, whose timepieces run on a solar battery, are doomed if the weather becomes unseasonably harsh.
Even the most precise avian clocks aren’t quite synchronized with man’s calendars. The swallows of Capistrano, which are said to return to the mission at San Juan Capistrano each year on St. Joseph’s Day, actually arrive within a week or so of March 19. And Hinkley, Ohio, residents conveniently close their eyes to the many Turkey Vultures that return before “Buzzard Day.” But overall these birds and species like them are at least as punctual as our airlines.
As days grow longer in spring, most of our familiar songbirds are unwittingly set on a course which will lead, in many cases, to a Northland arrival, production of young, and a return trip south. But in other cases, this course leads to death, which is why the survivors have so many babies each year. Migration is treacherous–before there were high rises, TV and radio towers, and other man-made hazards, migrating birds faced predators and starvation on unfamiliar territory, unpredictable storms, and ocean waves which snatch low-flying birds and toss them about as so much flotsam.
The survivors have no choice but to reproduce as soon as they reach their breeding grounds. We with options in every aspect of our lives can only imagine what it is to be a bird, whose very reproductive organs depend on the heavens. Day length triggers ovaries and testes to shrink to virtually nothing by fall–so much excess cargo on the wing. A devoted pair of geese, mated for life, are limited to platonic love for most of the year. And when the days lengthen again, whether they want to or not, their bodies must prepare for new life.
Bluebirds are among the early migrants in spring, which means that this extra day might be a good time to clean out bluebird houses or set out new ones. You won’t catch presidential candidates thinking of bluebirds, today—like birds, they’re wearily migrating from state to state in a desperate struggle for survival. The odds are even worse for them than for most birds, though–all but one will fail.
(Recording of an Eastern Bluebird)
This is Laura Erickson, and this program has been “For the Birds.”