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Wisconsin Natural Resources magazine

Wisconsin Natural Resources magazine

A male lesser scaup. © Scott Nielsen
A male lesser scaup.

© Scott Nielsen

February 2001

Flight of the bluebills

Scaups scoff at winter weather.

Robert J. Zimmer

A raft of ducks | Northern migration

The bay was nearly frozen; the nearshore waters encrusted in an ever-thickening sheet of clear, flawless ice. Low-hanging clouds, dark and swirling, rolled across the sky from shore to shore on a driving east wind. Angry whitecaps lashed at the fringe of the ice shield a hundred yards out over deeper water. It was late fall...winter had arrived early, and so had the bluebills.

Skimming across the dark choppy waters, a small flock of the hardy ducks circle low to the surface before crashing down amidst a much larger raft of the birds already assembled there. "Bluebills," a colorful name commonly given to a pair of stocky diving ducks known as scaup, are highly gregarious birds in fall and winter, toughing out the season's worst in tremendous open water flocks known as rafts.

Here in Wisconsin, visible from the shores of mighty Lake Winnebago, the first flocks have arrived and will remain as long as open water allows. When the lake freezes over completely, the majority of the birds, instead of flying south, will gather farther upstream along the swiftly flowing waters of the Fox River, playfully enduring the bone-chilling cold and winter's heavy snows. The flight of the bluebills is on.

The two species of scaup – the Greater and the Lesser – are so much alike, and the characteristics that separate them in the field are so slight that often only experienced observers under good light conditions can distinguish between them. When in full plumage, the greater scaup male differs from the lesser by its greater size, thicker neck, and by the fact that the head has a greenish irridescent sheen while its smaller cousin displays a glossy purple. Females of both species are colored brown overall with a telltale patch of white around the bill across the face.

Here in Wisconsin, following the height of fall migration when both species are well represented on our waters, it is likely that most bluebills encountered through early spring will be lesser scaup. This bird shows a decided preference for interior lakes and ponds of moderate depth and associated low islands, bulrushes and brushy coves. The greater scaup, on the other hand, inhabits more marine, brackish and saltwater environments along the Atlantic and Pacific coasts and normally only passing through our state en route. Large numbers however, do remain throughout winter along coastal Lake Michigan waters.

In either case, when the flight of the bluebills begins, we're in for quite a show indeed!

A raft of ducks

Hardy birds, like all marine ducks, scaup are especially late in arriving each autumn. Few are seen until November, well after some of our earlier migrants have departed for warmer southern climates. At first, they seem inclined to keep far out on the open waters of larger bays and lakes, giving hunters little chance at them until severe cold and wind drives them in.

Scaup feed by dining largely on clams, mussels and other sluggish marine life. The first flock settles on the water over a promising mussel bed or clam flat and soon begins diving actively. Another flock passes, sees the activity and joins in, and so on ... and so on ... until there may be hundreds, even thousands of birds.

These huge rafts usually stretch out into a long column and keep swimming until the ducks have taken their fill, the bright white backs of the males glistening brilliantly in the sunshine. Together with canvasbacks, redheads, goldeneyes, mergansers, buffleheads, ring-necked ducks and oldsquaws, scaup form wonderful fall migration spectacles here on Lake Winnebago. Huge floating flocks are visible from almost any shoreline vantage point through late October and November.

Scaup go by a number of different monikers in addition to "bluebill." Other common names include the mussel duck, blackhead (as both species appear black at a distance), blackjack, broadbill (the blue bill is also rather flattened and broad for securing their underwater prey), and raft duck.

Lesser scaup breed from central Alaska through the boreal forests of Canada and south through Michigan, Wisconsin, Minnesota, the Dakotas and Montana. South and east of this area, they are decidedly sporadic in their nesting attempts. Wintering birds can be found scattered on larger lakes and rivers throughout the Midwest and Great Lakes region, while the largest numbers by far travel to the Atlantic and Gulf coasts as well as the Pacific coastline, Cuba and even northern South America.

Their movements from north to south are far from simple. Many of the prairie breeders, are undoubtedly closer to the Pacific, but migrate southeastward to winter along the Atlantic via the Great Lakes. Even some Alaskan birds follow this transcontinental route, while huge numbers pass straight south through the interior to reach the Gulf coast via the Mississippi. Even birds from eastern areas of the breeding range that winter in Florida will backtrack slightly to the west to follow this route rather than pass along the Atlantic Coast. Needless to say, researchers are continually amazed by their findings regarding the migration patterns of these ducks.

The flight of the bluebills is strong and fast. These heavy-bodied, squarely built birds are powerful fliers once they are launched, but normally must run along the water with wings

working frantically before they actually become airborne. In the air, they have a rapid wing beat and short, chunky appearance. Flocks of 25-50 birds are common, especially on long flights. There is no regular formation to these flocks, though occasionally a small flock may assume the shape of a wedge. If the flock is excessively large, it may string out to great lengths, bunching in places. In flight, the birds have a habit of alternately twisting their bodies from side to side, flashing dark and light.

The most important identification mark between the two species in flight is a white band along the back of the wing. In lesser scaup, the white stripe extends only part way along the wing, while in greater scaup the white extends nearly across the entire wing.

Scaup are prime favorites with many sportsmen as they fly fast and decoy well to furnish quite a challenge. Best days for success are often the windiest, icy days of late October and November when the playful ducks dart to and fro over the choppy waters during Wisconsin's famously violent easterly squalls. Haunting the open waters, just beyond sight in the snow, mist or rain, these ducks thrive in this type of weather, seemingly quite happy and indeed enjoying our cold November gales.

Many a hunter has returned with heartfelt admiration and respect for these swift and determined waterfowl. The scaup is an excellent swimmer and diver, diving usually with closed wings, using its immense padded feet to propel it through the water. When wounded or pursued, whether by hunters or predators such as fox, eagles, or lynx, the resilient scaup will employ every artifice to conceal itself, keeping mostly underwater and, in some cases, forcing itself under aquatic vegetation where it sometimes becomes entangled and drowns. If all else fails, the bird may even seize some underwater plant with its bill and as a last resort, hold on until death ensues in its anxiety to escape its pursuer.

Northern migration

Come spring, scaup have the most protracted migration of all species of duck. Some start northward as soon as early February, while others may not leave until May. First arrivals on the northernmost breeding grounds usually can be found in midApril, while the major influx wings in during the later parts of May.

Forming pairs on the wintering grounds as early as December, the birds arrive ready to nest. The female selects the nesting site, walking into and carefully inspecting grassy areas near the shores of boreal lakes, sloughs, marshes and prairie potholes or even flying to distant upland areas. The male always follows close behind on these forays, often followed by a second hopeful drake.

Female lesser scaup. © John Bartholmai
Female lesser scaup.

© John Bartholmai

Among the last ducks to nest, scaup lay between six and fifteen eggs, which are in turn incubated by the female for 21-27 days. The first young are normally seen around mid-July. Young scaup are seemingly extraordinarily excitable, playful and wild creatures, apparently fond of jumping straight up and dashing about near the nest like kittens.

Hens often desert their young while they are still in the downy stage, and most broods are on their own by the age of four to five weeks. The deserted young may join other broods or entire families may join together with two or three hens combining their broods into one large amalgamation. As many as 55 youngsters may form a single group with several females in attendance.

Males, meanwhile, move to molting grounds and are followed closely by non-nesting females. Early nesters that have left their broods behind are next to arrive. Often, these molting grounds are well north of the breeding range, and some may contain quite incredible concentrations of birds. One lake in Saskatchewan carried an estimated 25,000 lesser scaup per mile of shoreline!

Following the molt, and the regained ability to take wing, the whole population moves on to its winter quarters, and the flight of the bluebills begins once again.

Avid birder Robert J. Zimmer writes from Neenah.