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Redhead

By Gael Bissell

Each spring, just after the ice melts and the bulk of the Northern Pintails and American Wigeon pass through our waters, I quickly look for the brightly colored Redheads (Aythya americana). I am not sure why I like these particular waterfowl; perhaps it’s because when I see them in the Flathead Valley, they are in small groups and are a bit less common. Although Redheads aren’t as brightly plumed as Harlequins or Wood ducks, the male’s rufous head and neck lights up when it catches the sunlight. This waterfowl’s red head contrasts dramatically with its black chest and grayish back and black tail. The Redhead’s round and lighter head and blueish, relatively small bill help distinguish this species from the also reddish-colored, rather heavy, straight-billed cousin, the Canvasback. Redheads sit rather upright in the water, and they are a bit smaller than mallards, usually 19-20” in length. In flight, they look much like a mallard with shallow but faster wing beats.

All of the five species in the genus Aythya (Canvasback, Tufted duck (west coast), Ring-necked duck, and Greater and Lesser Scaup) are divers, feeding on aquatic invertebrates, insects, and plants. Apparently, the six species can interbreed with only the male hybrids identifiable.

Redheads nest primarily on permanent and semi-permanent non-forested marshy lakes and ponds, with the highest densities reported in the Dakotas, Saskatchewan, and Manitoba (Fig. 1). They also nest in high numbers in the Salt Lake area of Utah, eastern Montana, and the Mission Valley south of Flathead Lake. Redheads winter in large mixed flocks mostly on hypersaline southwest lakes and sheltered saltwater bays along Mexico, the Gulf Coast. They are tolerant to salt in winter (like loons), one of the characteristics that differentiate Redheads from Canvasbacks and points to an evolutionary origin in the arid areas of the West. In spring, Redheads tend to migrate in small groups, arriving in our area just after the peak migration of mallards and Pintails. As they move through or settle on non-forested local ponds and wetlands, the males and females are quite active and noisy, bobbing their heads in the annual mating ritual for this species. Maybe you’ve heard the male make a far-carrying catlike, nasal “waow?”

Probably one of the most interesting life history facts about Redheads is that they are parasitic! No, they don’t carry more parasites than other waterfowl. They, like cowbirds, will place their eggs in the nests of other waterfowl (Mallards, Pintails, Scaup, Teal, etc.) to increase their chances of reproductive success. Actually, some authors called them semi-parasitic. Under stressful or poor conditions (e.g., dry years), younger females are entirely parasitic while older females nest normally. During normal water years, females will lay 6-10 parasitic eggs in other waterfowl nests prior to their own nest building. In some cases, particularly as waterfowl densities increase, Redhead parasitism will decrease the productivity of the host waterfowl species.

Locally, you can see a large number of Redheads both migrating through and breeding in the Mission Valley pothole area of Ninepipe National Wildlife Refuge, Ninepipe Wildlife Management Area, and associated Confederated Salish and Kootenai tribal wildlife lands. Redheads arrive in pairs in March and rest/feed on the larger water bodies. Those that remain after April soon move to the smaller, shallow wetlands where they will either parasitize other waterfowl nests and/or nest or hatch their own broods. If successful, they will gradually move their own broods to larger and deeper wetlands.
A graduate study during the early 1960s in the Mission Valley found that, at that time, there were about 87-106 pairs of Redheads nesting annually in the Ninepipe area in densities ranging from 1 nest/5 acres to 1 nest/175 acres (average of 1/25 acres) depending on habitat. Only about 15% of the studied Redhead nests successfully hatched during the 1960s study, but this did not include results of parasitism. This information resulted in identifying the Mission Valley as one of the highest known nesting densities of Redheads in the lower 48 states. John Grant, Ninepipe WMA manager, reports that the size and overall condition of the Mission Valley pothole-wetland complexes have dramatically improved over the last 50 years due to increased protections by agencies and tribes and ongoing restoration and creation of new wetlands across this landscape. This area is also rich in nesting waterfowl that are not as common in the Flathead area north of Flathead Lake. Be sure to go on one of Flathead Audubon’s spring waterfowl tours to the Mission Valley to see these and many other waterfowl species typical of this rare pothole and grassland habitat in northwest Montana.

References:
* “Breeding Ecology of the Redhead Duck in the Western Montana,” John T. Lokemoen, Journal of Wildlife Management Vol. 30, No. 4, Oct. 1966, pps. 668-681.
* Ducks, Geese and Swans of North America, Frank C. Bellrose. Wildlife Management Institute, reprinted by Stackpole Books, 1976, pps. 314-324.
* “Life History Traits and Habitat Needs of the Redhead,” Christine M. Custer, U.S. Fish and Wildlife Service, Northern Prairie Wildlife Research Center, LaCrosse, Wisconsin. Chapter 13.1.11, Fish and Wildlife Leaflet, 1993.

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