Hawk Watching in Western North America

This story, by regular Out There With The Birds Contributor Jen Hajj, originally appeared in the July/August 2013 issue of Bird Watcher’s Digest.

Imagine a brisk September morning in the 1930s. Hunters gather at the gate to Hawk Mountain, a site in rural Pennsylvania known for the thousands of hawks that pass during their annual southward migration. The armed men find their places and spend the day shooting at the passing birds. Some are after food for the table; others seek to improve their hunting skills. But most simply want to rid the skies of “flying vermin.”

That was the sentiment of the day. Although federal and state laws protecting birds were on the rise and enforcement was improving, most birds of prey were exempt. Some states even had bounties on eagles, paying citizens for proof, usually in the form of a set of severed feet, of a kill. According to a report published in 1930, more than 70,000 bald eagles were shot from 1918 to 1930 in the Alaskan Territories alone.

Rosalie Edge, a saucy New York socialite, suffragist, and amateur bird watcher, read this report and was thoroughly disgusted. Shortly afterward, she founded the Emergency Conservation Committee and confronted the National Association of Audubon Societies (now known as the National Audubon Society) for not doing enough to protect all species of birds. In 1931, she filed suit against Audubon to obtain its mailing list and prevailed, and she subsequently wrote to some 11,000 members to inform them of their organization’s oversight. When she became aware of the shooting activities at Hawk Mountain, Edge did what she had the means and the heart to do. When it became available in 1934, she obtained a lease-buy option on the land and prohibited hunting. She hired New England conservationists Maurice and Irma Broun to watch the gate and describe the numbers and types of hawks passing through. The tradition holds to this day: Hawk Mountain Sanctuary continues as a center for the study of raptors, with annual counts averaging 18,000 birds.

In its infancy, hawk watching was primarily an eastern pastime. With few reports of migratory activity out West, many scientists assumed that western birds had a more dispersed migration than eastern birds. In the 1970s, an upstart wildlife biology student named Steve Hoffman challenged this notion. He had witnessed the inspirational migration at Hawk Mountain and wanted to be the first to find it out West.

Hoffman’s hunch paid off. Armed with maps, binoculars, and passion, he found the western flyways and established the region’s first scientific counts. Although many of these western migration monitoring sites did not boast the large numbers seen back East, the experiences were memorable for different reasons, such as the stunning western landscapes, rugged ridge lines, and the isolation. One of the original western monitoring sites—Goshute Mountain in Nevada—is still operational; each fall, watchers observe an average of 14,500 raptors spanning 17 species. Hoffman, still active in bird conservation and hawk watching, is now the executive director of Montana Audubon. When lack of funding threatened to close the Bridger Mountain monitoring site near Bozeman, Montana, he took it under his wing and kept it open.

Why do raptors choose these places for migration? They make their way using the geographical and wind features of the landscape, which facilitate soaring flight. Sparse hawk migrations can be seen virtually anywhere, but thermal updrafts, water features, converging mountain ridges, sheltered stopovers, and the availability of food concentrate raptor migration through distinct flyways. Sites where several flyways funnel together can be witness to more than a half-million birds during a few weeks every fall.

Though the sight of tens of thousands of birds is emotionally appealing, scientists are especially interested in the mathematical patterns. There are more than 400 hawk migration monitoring stations across the United States and Canada, some operating daily from August to November, others only on weekends and holidays. The data collected by volunteers and staff members are compiled in a database managed by the Hawk Migration Association of North America (HMANA), which can be used to calculate population trends for different species or geographic regions. These data, combined with the findings of other scientists and monitoring methods, supply the scientific community with a thorough view of the health and conservation needs of individual species.

Conservation value aside, watching hawks is a challenge and a treat. Observers usually start around 9 a.m., just before the sun warms the earth enough for thermals to generate. The raptors start rising on columns of warm air, gaining lift and giving birders and photographers time to identify and view the birds. The scientists have keen eyes: some are able to identify distant birds that appear to untrained observers as specks in the blue. At midday, if it is warm enough, the birds fly so high they are no longer visible to our eyes, even with the aid of optics. Yet, even with this midday lull, observers keep their eyes to the skies. Near day’s end, the birds drop lower, and eventually seek nighttime roosts.

Every day holds surprises. Long periods of silent scanning are punctuated with drama: a cursing kestrel bouncing off a golden eagle’s head, a sharp-shinned hawk hurtling by at eye level, a thousand Swainson’s hawks grabbing at a swarm of dragonflies. As the season progresses, the roster of raptors changes, starting with late-summer movements of kites, harriers, and accipiters and ending in November with the arrival of rough-legged hawks and bald and golden eagles.

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