We woke up to snow this morning – and the roar of a rising creek. No rocks rumbling, though, so it’s not out of control. Last night we saw a pair of harlequins up by the log jam, sitting a few feet apart on a tiny gravel bar.  Just beside them, a willow branch was flailing in the current and we figured it had been ripped out upstream. Then a dark shape rose underneath it, dragged it over to the bank and disappeared. A beaver. We watched for several minutes, but it didn’t re-appear.

This morning, standing on the bridge at Driftwood Canyon Provincial Park looking downstream – a pair of harlequins. We assumed it was the same pair we saw last night. Turning to walk up the creek, Lynn spotted another pair, just a few metres above the others – the first time we’ve seen two pairs at the same time on the same stretch of creek.

We’ve often speculated about their nesting habits – and wondered what effect high water has on them. I’ve excerpted this from The Bizarre Life of the Harlequin Duck by Gary Turback. It answers many of our questions:

Although classified as sea ducks, these avian mariners weigh anchor each spring and migrate inland to breed. The Pacific birds wend their way to rushing, tumbling mountain streams, while the eastern birds settle on turbulent rivers primarily in Quebec and Labrador but occasionally in Newfoundland. The Pacific harlequin is the only duck in the world that divides its time between sea and mountains.

In spring, breeding-age western harlequins–those two years and older–leave Pacific coastal waters for mountain streams in Alaska, Washington, Oregon, Montana, Idaho, Wyoming, Alberta, British Columbia, the Yukon and the Northwest Territories. A few even cross the Continental Divide to nest. Researchers believe some harlequins journey from sea to summit as anadromous fish do–by following streams.

Harlequin society is matriarchal, with adult females returning salmonlike to their natal streams to reproduce. “While on the coast, a young female picks out a bachelor to take home,” says John Ashley, a wildlife biologist at Glacier National Park. Because nesting females are more vulnerable to predation than are males, plenty of unpaired males also show up on the mating grounds, although they rarely get a chance to breed.

A harlequin pair may remain together for years, apparently with great loyalty. In 1992 on Washington’s Morse Creek, Schirato and fellow Department of Fish and Wildlife biologist Matt Nixon captured a female in a banding net, but her mate escaped downstream. Seeing his partner detained, the male returned to the net, repeatedly called to her and eventually became entangled himself. “I’ve never seen other ducks do that,” says Schirato.

In May or June, the female lays about six eggs in a nest expertly concealed in streamside vegetation, a hollow tree or logjam. The male now returns to the ocean, precluding any possibility of renesting if the eggs are destroyed. Oddly, some unpaired females choose this late time to migrate inland. “It’s possible,” says Ashley, “that these females might pass the ocean-bound males headed in the opposite direction.” The tardy females, which are young birds looking for future nest sites, do not mate.

With luck, a mated hen will produce a few new harlequins. “Generally, harlequin reproduction is rather abysmal,” says Reichel. “They don’t breed until they’re two years of age or older, they lay relatively few eggs, and they can’t renest if they lose their clutch.”

Mink, goshawks and other predators likely kill some ducklings, but probably a greater proportion of harlequin young fall victim to cold weather or high water. Raging streams do not bother the adults, however, thanks to swimming skills that sometimes seem almost fishlike. For them, no torrent is too turbulent. “Harlequins routinely navigate rapids–with water spraying and foam flying–that few kayakers would ever enter,” says Ashley.

The duck even feeds in the seething current, diving to force its way to the stream bottom. With wings held tight against its body and feet pumping rearward like propellers, the bird noses troutlike from rock to rock, searching for aquatic insects to eat. Meanwhile, the water churns around it. “It must be like swimming in a washing machine,” says Ashley. After 20 or 30 seconds, the harlequin bobs to the surface for air, then dives again.

For adults, the swift current provides the best defense against most dangers. When threatened, a harlequin simply swims into the watery maelstrom and is swept downstream to safety. On the relatively rare occasions when stream-dwelling harlequins fly, they remain low and follow the stream’s every twist and turn.

Practicing in quiet backwaters, young harlequins soon become adept at negotiating tricky currents. Before they learn to fly, however, their mother may return to the coast, leaving the youngsters to fend–and navigate–for themselves. “Some hormonal urge must tell the female to migrate now!” speculates Cassirer. “Fortunately, the young somehow know where to go when they later learn to fly.” The prevailing theory holds that hens (and the males before them) must return to the coast before their annual molt renders them flightless.

By late September, virtually all harlequins are in coastal wintering areas, where they congregate in substantial flocks and feed in the nutrient-rich intertidal zone. Often, they forgo protected bays in favor of the roaring surf. Violent water, it seems, is in their blood.