Wildlife Lovers Look to the Sky for
Hawks in Autumn
Photo by Vic Berardi
Standing atop a 190-foot-high former landfill at Greene Valley Forest Preserve, in Naperville, Jeff Smith gets a 360-degree bird’s-eye view of creatures he loves to watch—hawks. It’s September, and these birds of prey are migrating south for the winter. Their sheer size and antics in the sky, along with the stories they can tell about the environment, attract local wildlife enthusiasts to watch and count them.
Smith and other members of the DuPage Birding Club will count hawks through the last cold days of autumn at Greene Valley Forest Preserve. Vic Berardi, of Gurnee, and others count hawks at Illinois Beach State Park, in Zion, beginning sometime at the end of August through early December. Berardi started the state park watch nearly 20 years ago, and it’s now run by Paul and Janice Sweet, of Zion. In 2013, Berardi helped start a hawk watch at Fort Sheridan Forest Preserve, near Highwood.
He and other volunteers count birds called raptors—large avian species with sharp talons to snatch their prey. Species include red-tailed hawks, peregrine falcons, eagles, American kestrels, turkey vultures, merlins and osprey. Other non-raptor large migratory birds counted in the fall include sandhill cranes.
These serious hawk watchers tabulate data and send it to The Hawk Migration Association of North America, which hosts a website showing the population trends of hawks. However, anyone that wants to enjoy a free show featuring big birds doing sometimes crazy antics in the sky can stop by these locations in the Chicago region in autumn to observe and learn.
“It’s a mystery that unfolds. You don’t know what you’re going to see any particular day,” says Berardi. “Some days, it’s just a sight to behold; all these hawks coming through in waves.” He notes that hawks migrate on almost any day during the fall. “Basically, they are riding the good, steady winds coming from behind them. The sun heats the ground and the heat rises, creating thermals, or columns of warm air hawks can use to hitch rides and save energy.”
Some birds, like broad-winged hawks, red-tailed hawks, osprey and eagles, ride on those thermals. “They try to get as much lift as they possibly can from the thermals and get up as high as they can, and then cruise or glide until they get to the next thermal,” Berardi says.
What makes the Illinois Beach State Park and Fort Sheridan sites great places to observe the birds is the fact they are located along Lake Michigan. Hawks don’t want to go over that large body of water, so they tend to hug the shoreline until they find a better passageway, bringing them into the view of hawk watchers.
Hawks, at the top of the food chain, are considered indicator species. That means when their populations change, the health of the environment is also likely changing. In her book Silent Spring, Rachel Carson cited decreasing numbers of immature bald eagles seen at Hawk Mountain Sanctuary, one of the oldest hawk watches in the country, in eastern Pennsylvania, and attributed the decline to the use of DDT.
From the more years of data gathered, the more conclusions can be drawn, Berardi says. He has learned through years of observation and data collecting that broad-winged hawks, which migrate in large groups, are more prevalent at the Greene Valley Hawk Watch than they are at Illinois Beach State Park. “I think they’re following the Fox River, and they are so high up they likely see Lake Michigan and avoid flying over there,” Berardi says.
Different species come through at different times at all three sites. “At Greene Valley in early September, we see turkey vultures and red-tailed hawks, then come the peregrine falcons,” Smith says. “That’s a big treat. If there’s a good wind and other hawks are on the wind, hunting the hillside and the grasslands, peregrines come by and start playing tag with them.”
In mid-September, large groups of broad-winged hawks in the hundreds, and occasionally in the thousands, can be seen moving together on the thermals. Later on in the season, eagles start flying by. “We keep a tally board for the public to come watch, and they’ll stop by and ask what you’re seeing. There’s always somebody there to answer questions,” Smith says.
Not all hawks come within easy view, which makes them difficult to identify. Over the years, Berardi has learned to do so by observing their shape, flight pattern and any noticeable markings on the bird.
Sheryl DeVore is a Chicago area writer, editor, educator, photographer and author of three books on nature. For more information, email Sheryl.Devore@comcast.net.
Some Migratory Birds of Prey in the Chicago Region
Hawks and other birds of prey migrate through Chicago in spring and fall; some also nest here in the summer. Here are three of the easier species to identify in the sky during migration.
Turkey vulture – large black bird that flies with wings slightly upturned – September and October.
Red-tailed hawk – large, light-colored bird with red on the tail in adults – nearly year-round.
Bald eagle – huge bird with white tail and head in adults – more often in October and November.
Here’s what beginning hawk watchers need to know to prepare for a few hours in the field.
- Choose a day when winds are blowing steadily, typically from the north or northwest.
- Dress in layers. It can be cold along the lake front or at the top of the hill.
- Bring binoculars, lawn chairs, blankets, food and water.
- The best time to view hawks is mid-morning through mid-to-late afternoon.
How to Get There
Greene Valley is open from 11 a.m. to 6 p.m. on weekends in September and October. An access drive to the hawk watch, the top of a former landfill, is south of 75th Street off Greene Road, in Naperville.
Counters are typically at the Illinois Beach State Park north unit from around 8 a.m. to 4 p.m. daily during fall. From Route 173 and Sheridan Road in Zion, drive north to 17th Street. Turn east to enter the park, and then right at the sign for the Sand Prairie Day Use Area. Park near the first pavilion on the right. Outhouses and picnic tables are available.
The Fort Sheridan Forest Preserve, just opened after renovation, contains parking spaces for 50 cars, picnic tables, benches and outhouses. Enter Fort Sheridan at Sheridan Road and Gilgare Lane, in Highwood, and follow the signs to the preserve.