A male harlequin duck on the Chicago River would be a rare and beautiful sight. It has a curl of light feathers streaking over its forehead and swirling down its neck, cheeks that are a striking blue, and an animated manner that earned it the scientific name Histrionicus histrionicus, from the Latin for “melodramatic.”

The harlequin hen, by contrast, is a dull brownish black, with ashy patches at her bill and a white spot behind her eye. But it was a hen that turned up unexpectedly in late February at the low dam at River Park, just south of Foster on the North Branch of the Chicago River. I was paddling a kayak when I spotted the unfamiliar duck diving into the dam’s outflow, a spillway of roiling water.

The harlequin hen is a playful diver, opening her wings as she repeatedly propels herself beneath the surface, staying down for half a minute at a time. Most harlequins nest along the rapids of mountain streams in the Canadian west or follow rugged surf lines in the North Atlantic, hunting in waters too rough for other ducks.

River Park wouldn’t remind us of Saskatchewan, but this harlequin seemed to think the dam’s turbulence served the purpose. The foot-long bird plunged underwater to scavenge, came up to the surface, paddled powerfully toward the waves under the dam, then turned to surf down the current and start again.

She caught the hum of a fisherman’s boat before I did and, with a surprising burst of speed, paddled to a rock and rode out the boat’s wake. I never saw her fly, and her wings didn’t look strong. If I didn’t know better, I’d have guessed she’d head north in the spring by swimming.

A few days later Joe Lill, a music professor at nearby North Park College and a member of the Chicago Audubon Society’s board, walked over with me to see the exotic little bird again. Harlequins winter in New England and New York, and they occasionally stray into the Great Lakes. But they’re quite unusual inland. If you have a serious telescope, a hardy constitution, and the patience, you can track one down somewhere on Lake Michigan most winters. But no one in the tight circle of Chicago birders remembers a river sighting, so Lill has been charting the hen’s stay, and plans to visit the dam every day till she leaves.

Serious birders are incessant list makers, and Lill is no exception. He has a life list of birds he’s seen, and a separate list of just those he’s seen in Chicago. He says, somewhat defensively, that he’s never kept a list of birds around North Park College. “My friends up at Lake Forest College are right on a curve of the North American hawk migration route,” he says. “I just didn’t want to compete with them. But this week I told the biologists here at North Park that the epicenter of Illinois birding was about a block away, and I decided I’d better start keeping a list for the neighborhood.”

Lill grew up near the river, south of Montrose. “But I didn’t bird then,” he says. “I wish I had a list from when I was young to compare. We recognized great blue herons then. We would see them along the river, but I can’t say how often.”

In a short walk along the river, he and I saw not just the harlequin but kingfishers, night herons, and even a great blue. We also saw ducks–mallards, blue-winged teal, mergansers, and goldeneyes. The day I’d first seen the harlequin I flushed a large flock of goldeneyes near the Diversey bridge. They’re also known as whistling ducks, and the more than 100 birds announced their presence with their whinnying flight before I saw them. The urban rumble drowned in the whistle of wings.

“I think ducks like open points on the river,” Lill explained as we stood beside the dam. “You see them here and at Diversey and North Avenue–places where the river opens wide. Whether it’s more like their prairie lakes in Canada, where they breed, or because they can see predators, I don’t know.”

Most birds fly south for the winter, and for these birds Chicago is south. In fact, late winter is the best season for ducks in Chicago. Birds of Chicago, an illustrated guide to the most common species seen here, lists 14 ducks, though only 3, including the ubiquitous mallard, remain common in the summer. The rest scatter north across their breeding territories.

In winter the ice cover gathers waterfowl together, and a walk along the river or the open water near the Shedd Aquarium can turn up five or six species in a few minutes–goldeneyes doing their amusing mating displays, buffleheads and mergansers diving, redheads paddling and dabbling, sooty coots, as well as delicate little grebes, which are reasonably friendly, perhaps because they’re too small and too gamy for hunters.

The crowds of waterfowl on the river, not known for avian diversity for many years, offer a reassuring message. The bottom must be providing a fair amount of food for the diving ducks, hunters of small crustaceans, mollusks, and fish. Harlequins are mostly carnivorous, and they prefer spots where water flows out of mountain lakes, which have richer gleanings than places downstream. The icy beard on the dam at River Park divides the open main channel of the North Branch from the ice-clogged upper reaches–here more than 30 miles of streambed finally surface, and small fish, starved of oxygen under the ice, tumble stunned over the little waterfall into the bill of the lurking harlequin.

A decade ago fewer than 1,000 harlequin ducks nested in eastern Canada. These eastern flocks have since come back, but their future may depend on individuals like this hen finding unlikely havens in the winter. “I don’t know how she found this place,” Lill said as we watched her. “I sometimes think it’s bittersweet when I see a rare bird. Something’s wrong–the radar’s not working, and they’re off course, probably not going to make it home.” But, he added, harlequins do show up on the lake, so the river isn’t too far afield. The hen’s small size and dull facial markings suggest she’s a young bird. Mature harlequins should be half again as large, just smaller than mallards.

It’s not uncommon for immature birds to move into new habitat, tracking down their relatives only on the summer breeding grounds. “She’ll probably pair up next year,” Lill said.

Soon the hen had attracted a pair of curious companions–a male and female mallard that swam very close to her. When they first paddled up, she dove, and I wondered whether they’d intimidated her, but she popped back up in the same place. Maybe her diving stirred up seeds and plant matter for them to eat.

After a few dives, the mallards seemed to lose interest and swam to some rocks across the river. Moments later the harlequin surprised us by joining them. “It’s almost like she’s following her parents around,” Lill said. “She thinks she’s a mallard.”

When they all got back in the water we noticed that she cocked her head back and forth when they swam near. She was probably trying to communicate something, but we had no idea what–and no idea whether the mallards understood either.

A couple carrying binoculars walked up to the dam. Charlie and Bill Branson were birders who’d come over from Lakeview to track down the little duck they’d heard about by E-mail. They said they’d once traveled to Winthrop Harbor on the Wisconsin border just to see a harlequin.

Soon a young woman in a full-length coat and fur-lined hood strolled up. She said she wasn’t a serious birder, though she’d consulted a field guide and identified the duck. She walked by every few days just to see if the harlequin was still diving into the spume. “The way it dives, it reminds me of seeing loons at camp when I was a kid, up by Lake Superior,” she said. “We used to chase them. There was a whole family of them on the lake. We’d try to get close in canoes, but they’d dive and come up farther away.”

Other people stopped by–two middle-aged power walkers, a few more birders, a young man on his break from the local Burger King. Showing no signs of stage fright, the harlequin kept diving, 20 feet away, until the sun fell so low the water grew murky. Then she swam to some rocks, stepped up, shook her wings dry, and tucked her head to her breast.

Art accompanying story in printed newspaper (not available in this archive): photo/Jim Newberry.