A small, sexually dichromatic cardueline finch. Generally drab gray-brown with heavy streaking below. One of the most striking features of House Finches is their extreme variation in male plumage coloration. In all populations males vary in color from pale yellow to bright red on crown, back, eyebrow stripe, cheek, shoulder patch, rump and ventral plumage. Some females show faint carotenoid pigmentaion on the rump, crown, and breast but never as bright as males. Juveniles resemble adult females but are more finely streaked below (Hill 1993).
For a comprehensive review of the conservation status, habitat use, and ecology of this and other Montana bird species, please see Marks et al. 2016, Birds of Montana.
Western Hemisphere Range
A common backyard bird throughout most of the contiuguous United States. In its native west, this species occupies a wide range of open or semi-open habitats from undisturbed desert to highly urbanized areas. In the east, it is rarely found far from urban or suburban areas. Throughout its range, it has a fondness for feeding stations and for nesting conspicuously around buildings (Hill 1993).
In all seasons, 97% of diet is vegetable matter including buds, seeds, and fruits. Primary weed seeds eaten include Napa thistle, black mustard, wild mustard, Amaranth, knotweed and turkey mullen, plus some 21 additional seed varieties. In late summer it will eat fruits (Hill 1993).
Socially monogamous. Pair formation begins in winter flocks. Searching for nest sites is a conspicuous behavior throughout the nesting season. A wide variety of nest sites are chosen from pine and spruce trees to rock ledges to vents, ledges or ivy on buildings. Most females nest more than once during a breeding season. Clutch size varies substantially in all populations with an overall range of 1 to 6 (Hill 1993). Nesting dates are probably similar to those for Wyoming: April 27 to August 16.