Her short silver hair pokes out from beneath a rock-climbing helmet, and her black fleece jacket wards off the cool air flowing from the cave. Since Potter has made the arduous trek here once a year to monitor the birds. Also along for the adventure is local photographer Todd Patrick, who has taken hundreds of pictures of the birds and researchers during the past several years.
To reach the cave, the group hiked for three hours, losing 2, feet in elevation over three miles before covering the final foot drop along a scree-covered slope to the cave hidden below. This afternoon they banded the chicks, using an foot ladder they keep stashed nearby to reach the lofty dwellings. She jumps up, nimbly crosses the jagged rocks like the long-distance trail runner she is, and disentangles the bird in a few seconds.
While she and Gunn examine the swift, Beason crouches near the net, watching for the next captive. Lustrous gray-black body feathers fade to light gray on the face. She has enormous black eyes and a petite nub of a beak.
Out of the Shadows: Black Swifts, North America's Most Mysterious Birds
Her curved wings measure 6. Referencing the leg band against a log—ID number —Gunn gives a little squeal. Throughout the West these researchers are hiking to remote waterfalls and caves, bushwhacking through grizzly country, and scaling slippery cliffs in search of more nesting sites only about have been documented.
Since swifts are nearly impossible to locate on the ground and can likely exceed mph in flight, population estimates are sketchy. The total population, estimated at 15,, is thought to be declining about 6 percent a year, Breeding Bird Survey data shows.
In fact, the federal State of the Birds report, coauthored by Audubon and other conservation groups, rated the species as the western forest bird most vulnerable to climate change. Because it depends on water flow at nesting sites, the predicted loss of glaciers and decreased precipitation could shrink suitable breeding grounds. The species was one of the last North American birds described to science, in Nearly a half-century passed before the first nest was found, in , on a sopping-wet coastal cliff in California.
Most of the documented nesting sites are in Colorado, where swift detectives have been most active, though one or more breeding areas have also been found in British Columbia, Alberta, Montana, Idaho, Utah, New Mexico, Arizona, Mexico, Central America, and the Caribbean. Sometimes a decade passes between discoveries. The first site in Oregon was uncovered just this past summer.
To complicate matters, swifts are exceptionally evasive. The tireless aerialists can cover hundreds of miles a day in search of food, spending 10 or 12 hours on the wing often at heights too high for the naked eye to see. And when they return to a nesting site, they might shoot through a curtain of water so quickly that even a careful observer could blink and miss it.
Take ornithologist Owen Knorr.
From through Knorr documented about 80 nests at 27 sites in Colorado. Only six more colonies were discovered in the state in the next half-century. In , under his guidance, the observatory joined forces with U. Thanks to the devotion of the likes of Knorr and Levad who died in and , respectively , black swift enthusiasts now recognize the hallmarks of likely nesting sites: water, a lofty position, inaccessibility, darkness, and unobstructed flyways.
These days they use mist nets and modified fishing nets with extra-long handles to catch adults, but reaching some nesting sites still requires ropes, ladders, and a sense of adventure. Close observation of the birds on their breeding grounds has helped paint a general picture.
Both the male and female care for the chick. At first they stay close, feeding it periodically during the day. In a couple of weeks, after the chick develops a thick downy coat, the parents start to forage from dawn until dusk, regurgitating insects throughout the night to feed their only child.
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Incredibly, it seems that the maiden flight is the first leg of migration. In that time she has recorded only one fledgling returning to the nest, for one night during a fierce thunderstorm. One particularly perplexing mystery is how the chicks survive alone for hours on end, their feathers ever damp; the leading theory is that during the day they go into torpor, a hibernation-like state, to conserve energy and keep warm. Other questions include what they eat down south and where they roost—or if they roost.
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The Colorado team is turning to technology to solve some of these riddles. The swifts carry them in a special harness Gunn designed and made. Alarmingly, the Amazon is rapidly being cleared for agriculture.
Mystery Diagnosis and the Case of the Unidentified Bird Shadows
One computer model predicts that by up to 30 percent of the forest cover in the part of Brazil where the birds winter could be lost. Beason and his colleagues are talking with a researcher in South America, hoping that the recent findings will spur studies of black swifts there. For instance, if huge numbers of swifts congregate in one area in winter, conservationists could fight to protect that critical habitat.
Unfortunately, the current transmitters are too big for swifts, though the Colorado team expects smaller devices will be available in two or three years. Meanwhile, Gunn is spearheading cutting-edge genetic analysis that will give a clearer picture of the population size and diversity. Team members have already collected blood samples from three dozen swifts, and they gathered feathers from birds throughout the breeding range this year. DNA samples allow scientists to decipher how diverse the populations are.
She hopes the analysis will also provide a more accurate population estimate. While the Colorado team forges ahead on the technology front, groups in other states are scouring the wilderness for new nesting sites. In Montana, where three active swift sites are known, that means risking the occasional run-in with a deadly predator, as Daniel Casey discovered in That year Casey, an American Bird Conservancy biologist who lives south of Glacier National Park , spearheaded a statewide effort to visit 32 potential nesting sites—places where swifts had been spotted flying above waterfalls or areas that would seem to offer ideal habitat.
They watched a number of feeding swifts, trying to see if any zipped into the falls.
I was surprised to see a shadow along the side of the head above the auriculars ear patch on many birds. I had never noticed this before studying albino birds. I also noticed a heavy shadow on the lower belly and flanks where the body curves away from the wing. This shadow helps describe the curvature of the body. In many photos there is also a shadow between the primary and secondary feathers where the edges of the secondaries pile up.
You will find a smaller number of photographs taken on bright sunny days. These photos will show crisp shadows that are deeper in value than you see on overcast days. By analyzing photos from sunny days you will get an idea of how to depict birds under these lighting conditions.
Once again, look for that shadow above the auriculars, on the flanks and undertail coverts, and edge of the secondaries. You may see shadows at the edge of the scapular feathers above the wing. Copy a few of these photographs to train yourself to understand how shadows wrap around the body of a bird.
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