The Long and the Short of It

We’re all familiar with the impossibly loud blasts emitted by tiny spring peepers in March. But have you noticed that peepers peep again in early October, not from ponds, but from the woods? In the fall this song as tentative as the spring peep is unabashed. And white-throated sparrows, those champions at belting out a decisive tune in the spring, now squeak out a comically out-of-whack, uncertain version of their song. Does something in the brains of these animals tell them that it is spring, in spite of the fact that now their vocal cords aren’t geared up for song?

Perhaps it’s the number of hours of light in a day – a stimulus that I may be reacting to as well. I get a return of the compulsion to garden in mid-September when, it turns out, there are about 12.5 hours of daylight at our latitude – just about the same amount of light there was when the urge last hit me at the beginning of April. Around here quite a few weeds have their way with the garden beginning in midsummer, but they’re in for trouble as the days shorten.

Or is it the rapid rate of change in the amount of light in a day that activates some region of the brain of the peeper, the white-throated sparrow, and some of us humans? The long days of summer linger nicely and the long nights and dark mornings of winter seems relentless compared to the speed at which day length changes around the equinoxes in spring and fall. This time of year, light is being subtracted so fast it seems we need to run to keep up.

The pineal gland, which responds to light and keeps track of circadian rhythms, is thought to be vestigial in people, but I quite like mine. Whether it’s imaginary or real I’m not sure, but the idea that we might experience the seasons physiologically is kind of fun to play with.