Introduction

The Purple Finch, a sexually dimorphic species, is moderately common across the northern United States, southern and central Canada, and the west coast of North America. The male, with its complex warbling song and raspberry red coloration, is one of the more conspicuous birds in its range. The female, by contrast, is an inconspicuous, drab, sparrow-like bird. Primarily an inhabitant of moist coniferous forests during the breeding season, this finch also breeds in mixed forest, in ornamental plantations, and in clearings associated with bogs. During the winter, it ranges throughout much of the eastern United States and southern Canada and migrates into lower-elevation areas in the west. It feeds almost exclusively on buds and seeds and is frequently observed at bird feeders.

The Purple Finch is noted for quasicyclical irruptions across portions of its winter range, thought to be associated with year to year variation in the production of northern conifer cones. Although widespread and regularly seen, this bird is one of the least-studied finches in North America because it is neither common enough to be easily studied nor rare enough to be threatened with extinction. Detailed studies of the Purple Finch have been restricted largely to patterns of its population dynamics (Kennard 1977, Wootton 1987), to population demography and structure derived from banding studies (Magee 1926, 1936a, Blake 1967, Yunick 1983a), and to intra- and interspecific aggression and flocking (Popp 1987, 1990).