On the fly
In a rush for winter, fall migration sweeps over us
Suddenly, the days seem shorter, the mornings light-sweater cool.
The sun, which only a few weeks ago peeked much too early into our home, no longer clears the immense cottonwood in the side yard until late in the morning.
The shower of birdsong that since spring awoke us before dawn and often carried into the dusk is but a whisper, and only the Eurasian collared doves, those inextinguishable year-round lovers, are making like it’s last dance at the prom.
We are in the midst of the fall migration, which for birders is as exciting, although perhaps more demanding, as the spring when it comes to seeing feathered migrants pass through the neighborhood.
Already the fall exodus is in full tilt, and that broad rainbow of millions of birds that swept over us in the spring is redoubling its tracks for winter havens to the south, tying together the ends of its yearly cycle.
But unlike the spring migration, when thunderclouds of birds boiled out of the south, the fall migration is more spread out.
The migration continues into December for some species, especially shorter-distance land birds (e.g., sparrows and blackbirds), raptors, waterfowl, and seabirds. Birds may move every day or may wait for favorable weather patterns to lift them on their journey.
Although generalizations often fall short when speaking of creatures whose natures it is to rely on nature, here are some clues from local birders and national birding sources.
First, fall migration starts earlier than you might think.
Some shorebirds start to move in late June and by late this month the passerines, those small songbirds we chase through the forest in spring, are headed south.
“The peak for passerines is late August,” wrote Coen Dexter of Nucla in a recent email. “Non-passerines — geese, ducks, gulls — is October.”
He said fall migration for passerines — which amount to half of all bird species — in western Colorado has been underway for a few weeks.
The only non-passerine he and partner Brenda Wright have reported as of Monday has been a shorebird, a Long-billed Dowitcher.
Some of the northern-most nesting Sandhill cranes also have started, but unlike songbirds, they mostly pass on without stopping, reports the Rowe Sanctuary in the Platte River valley of south-central Nebraska.
“The earliest we typically see (or hear) cranes is late September, with the peak of the migration occurring from late October through early November and ending sometime in December. During this time the cranes rarely stay for an extended period, usually just overnight,” says the Rowe website (rowe.audubon.org).
But don’t think fall migration is a bird here and a bird there sort of thing.
Nic Korte, who writes the Birds and More blog for The Daily Sentinel, recently reported on the WSBN list-serve site of seeing 17 different species in 15 minutes without moving from his perch.
“I thought I was in the tropics,” Korte wrote.
Actually, he was on Brush Creek near Collbran, and sitting where he knew he would find birds, at the edge of the aspen forest.
“There were several family groups,” Korte reported, including Western Tanagers, Purple Martins (some had fledged from a nearby tree within the week), Yellow-rumped Warblers and Green-tailed Towhees, among others.
“I’ve seldom seen so many landbirds in North America in such close quarters — and certainly not that many species of landbirds in such proximity.”
And on a recent morning, local birders Jacob Cooper (now doing graduate work at the University of Kansas) and Jackson Trappett headed to Pinyon Mesa, where they spotted Dusky Flycatcher, MacGillivray’s Warbler, Red-naped Sapsucker and Sharp-shinned Hawk.
And later, in what proved to be an extremely birdy day, the two “were shocked to witness an incoming flock of Purple Martins,” Cooper wrote in an email. “We counted 18 martins in view at once as they foraged over the aspens and drank from the lake in front of us.
“They soon disappeared to the south, but we heard one or two high birds calling sporadically for the rest of the morning.”