For the Birds Radio Program: More signs of spring
More signs of spring are being detected in the Duluth area.
(Recording of an American Robin)
Astronomers won’t officially declare the beginning of spring for two and a half weeks, and sensible people won’t pack away their winter coats until much later, but for ornithologists, spring officially began last Sunday, March first. Of course winter birds will be hanging around feeders for a while yet, and most Northland migrants won’t return until May, but there are already lots of encouraging signs of spring in the air. Steve Wilson heard a Boreal Owl calling its spring song ten miles north of Isabella last week, and one Boreal Owl may actually have been calling in Duluth, too. The problem with identifying a Boreal Owl by call is that it sounds quite a bit like a Common Snipe. The snipe makes a winnowing call with its wings:
(Recording of a Snipe)
Like all owls, the Boreal has silent wings, but it makes almost the same sound as a snipe with its mouth:
(Recording of a Boreal Owl)
Since snipe don’t normally return up here until April, a bird sounding like that right now is most likely the very rare Boreal Owl.
Other birds are acting like it’s spring, too, now. A Great Horned Owl has been hooting in Lakeside. Hairy Woodpeckers are flashing their white outer tail in amorous displays at one another–they’re the flashers of the bird world. All the woodpeckers and nuthatches are noisier now, and moving around quite a bit searching out territories. As many as 200 gulls are in Duluth–although most of them spent just about the whole winter here. And soon the northern owls and winter finches will pull up stakes and head north again.
But people will be most encouraged by the return of the geese and the robins. The migration of both species depends on temperature–they come back as soon as the temperature starts averaging 38 degrees. They follow the 38-degree isotherm, and if the weather suddenly turns bad, they’re capable of turning around and heading back south for a while.
Most other birds aren’t that lucky–their instinct in spring tells them to go north no matter what the weather brings. Birds that winter in the southern U.S., like Tree Swallows, White-throated Sparrows, and Yellow-rumped Warblers, return in late March or early April. These birds often get caught in an April Fool’s Day storm. This would be disastrous for most swallows and warblers, which need insects to survive. Fortunately, the Tree Swallow and the Yellow-rumped Warbler can both live on berries for a few days until it gets warm enough for insects again. If you want to help these early migrants during a spring coldsnap, you can set out some cheap grape jelly in a heavy plastic bowl on top of your feeder or porch railing. Robins and warblers will appreciate it.
Birds that winter in Mexico and Central America are far more influenced by daylength than by the weather–apparently weather forecasters don’t provide reliable information about the Northland over the tropical airwaves. So many garden favorites, like orioles and hummingbirds, will sit tight until May. But anticipation is half the fun of spring, so enjoy these last winter days.
(Recording of an Oriole)
This is Laura Erickson, and this program has been “For the Birds.”