Wednesday, March 31, 2010

The Quiet Ring-necked Duck

Ring-necked Duck pair in spring (c) John Ashley
Spring in Montana means fat snowflakes floating down in curtains, and then slowly melting away. And so it is with waterfowl migration as well.

Waves of fat geese, swans and ducks descend upon Montana to blanket the lakes as they ice out. Then the birds melt away, either flying farther north or spreading out into local nesting areas. Slowly, the spring spectacle gives way to a quiet summer.

One of the duck species that drops in can be easily missed. Ring-necked Ducks are not especially rare, but they are smaller and much less gregarious -- and so less visible -- than most of our other ducks. And as waterfowl go, the Ring-necks must quietly negotiate the bottom of the "pecking order."

Ring-necks become restless in the days before departing their wintering areas. During the day, small groups alternate between feeding and flying in circles above the pond. At sunset, flocks of 10-25 birds circle up above the pond and head north in a line, migrating at night.

Pair formation begins anew each spring, during migration in March and April. The male throws his head back and then turns his face towards a female while swimming away. If she's similarly inclined, she will swim after him. All of the females are paired by the time they reach their breeding areas, and a few surplus males are left over.

Female Ring-necked Duck (c) John AshleyThey normally arrive here between mid-April and mid-May. Ring-necked Ducks might cover Montana during migration, but they'll settle into the western two-thirds of the state for summer nesting. Then they seem to dissappear. They are smallish ducks that prefer the smaller, shallower lakes and ponds (less than 6' deep) for breeding sites. Wetland areas with thick, emergent vegetation -- especially flooded sedge meadows -- are preferred for nesting.

While nesting, the adults loose their winter weight gains. Fat reserves are completely used up by the female during ovulation, and she must aquire the protein necessary to continue egg production from the food she eats at her breeding site. She'll spend up to 19 hours a day eating while producing her eggs. The male feeds far less often while constantly guarding his mate. But he does not go to the nest once egg laying starts, and their bond dissolves while the pair is separated during incubation.

Nests are built in thick vegetation above water, and start out as weak platforms of bent-over vegetation. The female bends sedge stems over when she starts laying eggs, and a nest cup takes shape after several days. She lays one olive-brown egg per day, shortly after sunrise, and an average clutch in Montana is six eggs.

Ring-necked Duck hen with ducklings (c) John AshleyThe female incubates her eggs for 26-27 days. At day 25, the chicks start "pipping," or calling from inside the eggs, helping them synchronize hatching within six hours of each other. Early on the following morning, they'll leave the nest and start foraging. The downy chicks can swim on day one and dive by day two.

Ring-necked Ducks are opportunistic, omnivorous feeders. The diets of downy young and attending females is more than 90% animal matter. After one month, the chicks' diet has changed over to about 70% plants. Adult males and females eat about 85% plant matter during fall and slightly less during winter. Preferred animal foods include larval (aquatic) caddisflies and dragonflies. Plant matter eaten includes the seeds and tubers of aquatic plants.

Ring-necks have a more generalized diet than most ducks. This helps them colonize new areas, and areas of low productivity. Their breeding range expanded east of the Great Lakes in the 1930's, and west into Alaska and the Northwest Territories in the 1980's. While their distribution may be contracting along its southern boundary, it appears to be expanding everywhere else.

This expansion is intriguing, because they are so low in the "pecking order" and subordinate to all other waterbirds.

At their nesting areas, Ring-necked Ducks face attacks from territorial Pied-billed Grebes, American Coots, Red-necked Grebes and Common Loons. The latter two can kill adults and young alike. Females sitting on nests face predation from foxes, raccoons, Northern Harriers, Great-horned Owls, Bald Eagles and mink. Egg predators include mink, Crows and Ravens, raccoons, skunks and domestic dogs. Threats to ducklings also include pike, bass and turtles.

Many of the Ring-necked Ducks will survive this summer gauntlet, and fatten up before leaving in the fall. Similar to the spring flocks, they'll peel off and migrate at night in strings of 20-75 birds. Fall migration from Montana occurs between mid-September and early November. While a handfull of adults winter in far-western Montana, almost all of the Ring-necks east of the Cascade mountains will migrate down through the Great Plains and winter in Arizona, New Mexico and northern Mexico.

They'll spend the winter putting on weight and, come next spring, they'll drop out of snowy skies once more to quietly raise another generation of Ring-necked ducklings on our lakes and ponds.

Ring-necked ducklings feeding in the summer sun (c) John Ashley

Behind the bird: I've never figured out why these guys aren't called "Ring-billed Ducks." On their bills (top photo), the female has one and the male has two very visible rings, while the cinnamon collar around their neck is all but invisible.