Broad-winged Hawk Adult. Photo credit: Lillian Stokes

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“It is a late October day with cold brisk winds coming from the northwest. White, puffy clouds grace the deep blue sky. A cold front passed through late afternoon the day before. For the die-hard raptor lovers present at Illinois Beach State Park, this means that the larger hawks, the buteos, [birds with broad wings and short wide tails like the Broad-winged hawk] will begin arriving in sizable numbers,” writes Vic Berardi, leader of the Illinois Beach State Park (IBSP) Hawk Watch.

Mr. Berardi began the IBSP Hawk Watch in 2000. He erected his tent headquarters in the north unit of IBSP near Winthrop Harbor, also known as Camp Logan, on a nipple of a hill only a few feet above Lake Michigan. Paul Sweet, an ornithologist at the College of Lake County in Grayslake, is responsible for analyzing the data; Janice Sweet is the recorder.

The hawk watch lasts for 90 days, from the last Saturday of August until the last Sunday of November. Volunteers tally migrating raptors from 8 a.m. to 4 p.m., weather permitting. Janice Sweet reports above 500 birds two or three days a season, with most days logging between 6 and 49 birds.

Earliest arrivals at IBSP are juvenile red-tails, broad-winged and sharp-shinned hawks. Others in significant numbers add to the mix in a predictable sequence: osprey, falcons, broad-winged hawks in greater numbers (in 2003, more than 3,000 were seen in one day), Peregrine falcons, merlin, bald and golden eagles. Northern goshawks arrive in late October. The rough-legged hawk, which breeds in the Arctic tundra and winters in the Central U.S., makes a journey of eight weeks and 2,000 miles and reaches the Hawk Watch latest of all. Most frequently seen are juvenile red-tails and sharp-shinned hawks. Most adult red-tails do not migrate.

Mr. Berardi explains that knowing a species’ flight style and shape identifies it long before plumage is visible. “The smaller accipiters [short-winged, long-tailed forest hawks], like Sharp-shinned and Cooper’s hawks, can be very difficult to separate, and many of these we just term as Unidentified Accipiters.”

In some species, immatures migrate earlier than adults, and females migrate earlier than males. A Cornell study suggests a Cooper’s hawk’s migrating day may consist of half perching, 30 percent hunting, and barely 20 percent migrating.

Migrating hawks tend to move during the day, songbirds at night. Birds migrating south in fall must funnel down the vase shape of North America, often leading to phenomenal concentrations of many species. They tend to hug shorelines and ridges, following “leading lines” on the landscape. Some falcons have been tracked following the Edens Highway corridor. Raptors avoid the sustained flight necessary for flying over large bodies of water like the Great Lakes. They take advantage of rising air masses of wind over land associated with cold fronts, allowing them to simply ascend and glide.  Even Chicago’s high-rise buildings generate thermals that provide lift.

Amateurs and professionals alike flock to fall “hotspots” where migrating hawks concentrate on their way south. Watchers count them using a strict protocol. Results go to the Hawk Migration Association of North America. There are over 270 official watches. (Northward spring migrations occur across a broader front.)

Hawk Mountain in Eastern Pennsylvania is the grandmother of all Hawk Watches. Rosalie Edge is its heroine. Hers is not a household name but deserves to be.

A bright, cultivated woman, Ms. Edge was caricatured by some, who would learn better, as a “wealthy dilettante.” She was both a suffragist and casual birder, her life changed in 1929 at the age of 53. While vacationing in Paris, she read a pamphlet titled “A Crisis in Conservation,” written by Willard Gibbs Van Name. It detailed the slaughter of raptors by sportsmen at Hawk Mountain, with the complicity of the Audubon Society (not mentioned by name) in league with ornithologists at the Museum of Natural History. Hawks were anathema to many, including farmers protecting their flocks. John J. Audubon wrote, “For my part, I wish the Bald Eagle had not been chosen as the representative of our country. He is a bird of bad moral character, and does not make his living honestly.”

Rosalie’s son Peter says, “Thousands of hawks were killed each year and thousands more, wounded, were left to die on the mountain slopes. A local junk dealer made regular trips to the mountain to salvage the shell casings for their brass.”

Ms. Edge determined to stop the slaughter by “so-called sportsmen.” Her reaction unwittingly made her the first woman to have a major impact on conservation. She became a pamphleteer front for scientists whose careers would be endangered by speaking out. She created her own organization and news, addressed meetings and posed legal challenges with the likes of the ACLU on her side. She beat back the hunters and the professionals and caused the Audubon Society to reverse course and live up to its mission. In 1935, she purchased Hawk Mountain and deeded it over to Hawk Mountain Sanctuary Association. Hawk Mountain became the destination “to see the birds fly.” Rachel Carson used Hawk Mountain data for her book “Silent Spring.” Ms. Edge’s story is beautifully told in Dyana Z. Furmansky’s biography, “Rosalie Edge: Hawk of Mercy.”

A few years ago, on a glorious October day, hundreds of broad-winged hawks circled (kettled) in Evanston above the Dominicks’ parking lot on Chicago Avenue. Even the most ordinary places can provide a theater for this most extraordinary sight. A good day at the Hawk Watch is a marvel. 

Note: “The Stokes Field Guide To The Birds Of North America,” 

a new photographic guide with a large section on raptors, will be available in October.”