For the Birds Radio Program: Signs of Spring (Early Spring 2008)
Signs of Spring
Ornithologists and birders usually consider March first the first day of spring. Even if it still feels like winter, and even if astronomers sniff at the very idea of so blatantly ignoring the equinox, a few northern birds are starting to migrate, and it’s too confusing to think of the first Red-winged Blackbirds, Song Sparrows, and Wood Ducks as winter birds when they’ve clearly arrived from the south on their spring migration in early March.
Birds can burn up a quarter or more of their entire body weight during a single night’s journey—an ability I envy. When they come down exhausted after a long flight, a simple rest and feeding bout makes them as good as new. I can be in a rather dazed-like state for a full day after driving hundreds of miles even when it’s not through snow and ice storms—if birds shared that trait, they’d get gobbled up by the first predator passing by.
Our human schedules seldom reflect the natural world. Birds tend to fly ahead of storm systems, not right smack in the middle of them, and that’s despite the fact that birds don’t have access to weather radios or the internet to get the latest weather predictions. They feel it in their bones—quite literally, since their pulmonary air sacs apparently respond to barometric pressure. During an actual storm, rather than struggling along an interstate highway, they hunker down, usually on a fairly full stomach since one of their natural responses to sudden drops in barometric pressure is to pig out. Me, I have to listen to the weather report to have a clue about what I’m going to be facing on a long drive, and my drives are scheduled not by favorable winds and clear skies but by some event I’ve promised to attend or by needing to get back to work on time—factors entirely independent of weather. Fortunately, unlike birds my car comes equipped with snow tires and windshield wipers, but still, I think there’s something to be said for basing our activities on natural conditions, not some extraneous thing like an event calendar.
Spring migration for some species, especially robins, geese, Sandhill Cranes, Red-winged Blackbirds, and other early migrants, may not coincide with the coldest period of winter, but does happen during the worst of spring weather in terms of ice storms, blizzards, and wild temperature swings. There can be significant losses during these spells. Ice storms in particular hurt birds. Sometimes their feathers get coated with ice. At night their entire bodies may become encased with it, and cavity roosters are sometimes entombed and suffocated when ice coats their entrance hole. But birds have had tens of thousands of years to adapt to weather patterns, and so even as individuals succumb to weather, unless changes are extreme and dramatic, their populations tend to survive, slowly making adjustments to changes in the natural world as survivors reproduce, passing their own traits on to their young. The first robin of spring gets the jump on a great territory ahead of more cautious robins. He’ll produce babies who carry his early-migrating genes until the one spring when the weather is just too much for him. That year later robins will win the reproduction competition, keeping cautious genes alive, too. That’s the miracle of nature, and the nature of evolution. And watching these hardy survivors can provide us with endless entertainment and inspiration. That’s the nature of us.