Winter 2002

Rough-legged Hawk: arctic visitor

While I was taking a winter hike around the Hamilton Reservoir area near my house in Palatine several years ago, I looked up and saw a large black and white raptor circling not far above my head. I thought this quite brazen for a hawk, but it flew even lower, hovered briefly, and then dropped to the ground a mere 30 yards or so ahead of me. It was a rough-legged hawk, and it had caught a vole.

Photo: Joe Nowak

The rough-legged hawk (Buteo lagopus) nests on arctic cliffs, rock shelves, or trees near wide-open tundra. The female lays between two and seven eggs and normally does all the incubating and brooding, while the male brings lemmings to her on the nest. The male then does all the hunting for the growing young while the female stays close to the nest.

Rough-leggeds move from their arctic breeding territories south to wintering grounds in varying numbers each year, possibly due to fluctuations in prey populations. They are a coveted species on area Christmas bird counts.

Vic Berardi, hawk expert and raptor survey compiler at Illinois Beach State Park, says they arrive in the Chicago Wilderness area as early as late September. The peak period is from late October to the last week of November, and most are seen on days following an arctic cold front with WNW or NW winds of at least 15 mph. Some rough-leggeds will spend the winter in the area if they find suitable habitat, and leave to go back north to their breeding grounds by late March or early April. Berardi says he is awed to think of what a first-year bird experiences as it first soars over interstate highways and cities. He wonders if it notices his presence as he watches through his binoculars.

Rough-legged hawks are boldly and beautifully patterned. They occur in light and dark forms. Light birds show a general pattern of white underparts with dark bellies (adult male has a dark bib instead), dark wrist patches, and a dark tail band of varying intensity and width. The head is pale and the back is brown to grayish with light mottling. Dark birds look black from underneath except for the silvery flight feathers and base of the tail.

Wintering habitat is similar to breeding habitat – wide-open places like grasslands, marshes, and large fields with an abundance of voles and other small mammals. They often hunt by hovering over an area, or by quartering low over the grass like harriers. They also eat carrion, which makes them vulnerable to being killed by cars. They have been seen hunting in the larger grasslands of the Cook County forest preserves at Deer Grove East in Palatine, Paul Douglas Preserve in Hoffman Estates, and Crabtree Nature Center in Barrington. I’ve also seen them hunting over corn stubble fields in Lake Zurich, Long Grove, Buffalo Grove, and Libertyville. One of the most reliable places where birders could find rough-legged hawks each winter was the former Glenview Naval Air Station, but they have not returned since development has eliminated sizable open areas.

My rough-legged hawk stayed in the Hamilton Reservoir area for most of the winter that year. An ambitious local golfer practiced in the field and I saw the hawk hovering above him on several occasions. I’d be willing to bet that the golfer unwittingly stirred up voles that became easy pickings for the rough-legged. The last day I saw it, it was perched in a neighbor’s tree adjacent to the reservoir field and then flew to our yard and actually landed on the back fence. It was eyeing a squirrel in our yard, and my whole family was watching from the kitchen window. The squirrel seemed too calm, merely dodging to the other side of the tree trunk as the hawk swooped to within inches of it. I didn’t know whether to cheer for the hawk or the squirrel, but we were spellbound by the proximity of this majestic creature and the drama playing out before our eyes.

–Carolyn Fields