Montana Field Guide

Medium-sized dabbling duck. Length: adult males 57-76 cm, females 51-63 cm. Both sexes distinguished from other dabblers by slim profile, long narrow neck, and pointed tail. Sexually dimorphic plumage. Definitive Alternate male readily distinguished from other North American ducks by combination of chocolate brown head, white neck and underparts, and very long central rectrices. Female distinguished from other female ducks by slender proportions, pointed tail, mottled dull brown or bronze (rarely with some green) speculum, and mottled to spotted dark gray to black bill. (Austin and Miller. The Birds of North America, No. 163, 1995).

Normal migration periods in the Bozeman area are March 5-May 5 and September 20- November 20, with the peak occurring on October 20 (Skaar 1969).

Comments on habitat are found in Holm 1984. Summer birds prefer large lakes in the Bozeman area (Skaar 1969). Breeders favor shallow wetlands interspersed throughout prairie grasslands or arctic tundra. An early fall migrant, the species arrives on wintering areas beginning in August, after wing molt, often forming large roosting and feeding flocks on open, shallow wetlands and flooded agricultural fields (Austin and Miller 1995).

Grain (rice, wheat, corn, barley), moist-soil and aquatic plant seeds, pond weeds, aquatic insects, crustaceans, and snails (Austin and Miller 1995).

At Freezeout Lake the major cause of nest failure was skunk predation. Brood movement in southeast Montana tended to be from bare ponds to those with emergent vegetation, from small to larger ponds and to ponds with a lower water loss rate.

The species nests from late April through July, with hatchlings observed in May. At Freezeout Lake island nests were more successful (87.5%) than those in other habitats (all types averaged 34.4%). The average clutch size was 9.3; hatching dates were April 20-July 10.