Montana Field Guide

Large-bodied passerine, sexually dimorphic in size and plumage. Male mass 100 g, length 265 mm, nearly twice the mass of the female and longer by 50 mm. Adult male unmistakable: saffron yellow head, neck, and breast; body plumage, lore, and eye-stripe black, except for prominent white wing-patches visible in flight. Female and young male more muted in plumage: bodies dull black and brown, with pale yellow primarily on breast and throat, but also on neck and eyebrow stripe. White streaking merges yellow breast with brown abdomen. In both sexes, feet and bill black. (Twedt and Crawford. The Birds of North America, No. 192k 1995).

In the Bozeman area, normal migration periods are from April 25 to May 25 and August 20 to September 20.

Primarily prairie wetlands, but also common in wetlands associated with quaking aspen parklands, mountain meadows, and arid regions. Scattered colonies occur on forest edges and on larger lakes in mixed-wood boreal forest (Twedt and Crawford 1995).

During breeding season specializes in "aquatic" prey; feeds aquatic insects to nestlings. Consumes primarily cultivated grains and weed seeds during the postbreeding season (Twedt and Crawford 1995).

Nests located only over water, fixed to dead emergent vegetation from the previous year or fixed to robust growing vegetation. Nest is an open cup, compact and rigid. Eggs are generally subelliptical, grayish white to pale greenish white and profusely and evenly blotched and speckled. Clutch size ranges 1 to 5; mean 3.2 to 4.0. Near Fortine, egg dates range from May 28 to June 23. Statewide, nesting is from mid-May to mid-July.