As a child, I loved the song "Inchworm" from the film "Hans Christian Andersen." The movie was set in Denmark, but we have inchworms here, too.
Every spring, I was fascinated by the tiny creatures dangling from oak and maple trees on silken bungee cords.
Inchworms are not worms at all. They are the caterpillars of insects known as "geometer moths."
The name comes from Greek words meaning "earth measurer," which is fitting because these caterpillars really do appear to measure the ground as they move.
Unlike most caterpillars, inchworms are missing several pairs of legs in the middle of their bodies. So instead of crawling smoothly, they stretch their front end forward, then pull the rest of the body up behind them in a looping motion — inch by inch.
And when disturbed, they have another trick. Using strands of silk, they simply drop from branches and swing in midair. I'm still fascinated by them.
But inchworms are more than a curiosity of spring woods. They are an essential part of the seasonal food web.
Spring migration is underway just as many songbirds begin nesting. To raise their young, birds depend on the rich protein and fat caterpillars provide. For a warbler or chickadee feeding hungry nestlings, a soft-bodied caterpillar is far easier to catch than a flying moth.
The song says: "Inchworm, inchworm, measuring the marigolds… seems to me you'd stop and see how beautiful they are."
But caterpillars are not philosophers. They are eating machines, designed to turn leaves into the energy that will someday become moths.
But I see beauty. Those little "earth measurers" help make spring forests sing.
