Keeping track of migrating raptors
Scientists in Washington State monitor the populations and migration patterns of birds of prey, to identify trends.
The instant a black dot appears on the horizon, someone calls out, “We’ve got a bird out there,” and all chatter stops. The sound of a gentle wind pushing against the ridgetop is all that can be heard as wildlife biologists and visitors raise binoculars to their eyes to study the speck coming toward them.Skip to next paragraph
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Silence. More silence.
“A bald eagle, maybe?” someone asks.
Moments later, “Yes, a bald eagle,” biologist Brian Connelly confirms when the raptor is close enough for positive identification.
Satisfied, his counting partner, Craig Waythomas — also a wildlife biologist — puts it down on a clipboard page marked with 18 different species of hawks, falcons, and other birds of prey that might be seen from here.
Over the last 13 years, biologists have counted more than 27,000 raptors from this 5,500-foot ridge that separates the Methow and Chelan valleys. It’s about 40 miles northeast of Wenatchee. In the past 11 years, they’ve captured and banded more than 6,000 birds of prey, starting the leg-banding after two years of counting confirmed this was a good migratory route for birds of prey from late August to late October.
Principal biologist Kent Woodruff, who works for the US Forest Service in the Methow Valley Ranger District, says the collaboration between the nonprofit conservation group HawkWatch International and the Forest Service gathers valuable baseline data that will help determine when a species is in trouble.
“One of the things we’re learning is that raptor populations fluctuate, and some of that fluctuation is normal,” he says. A drop in the count of one species over a few years is no cause for alarm, he says. But over a decade, it becomes a trend, and can be an indicator that something’s wrong. The data so far shows no trends, up or down, of any of the hunting birds they count. “We haven’t seen anything that would be cause for action,” Mr. Woodruff says.
Each year, they count and capture everything from the extremely common sharp-shinned and Cooper’s hawks, to the less-often-seen prairie and peregrine falcons.
Among the rarest sightings from this location is the broad-winged hawk. Over the years, they’ve counted only 62 from this location of the tens of thousands of birds identified. On Sept. 28 they trapped and banded the first broad-winged hawk ever captured in Washington state.