Introduction

The Field Sparrow is a common songbird of eastern North America, breeding in brushy pastures and second growth scrub of the eastern United States and southern Canada and wintering slightly to the south of this. A partial migrant, some individuals remain on or near their breeding grounds in winter while others move farther south. This sparrow is well recognized for its distinctive song of pure tones, heard throughout the summer, that increases in rate to a trill. Both sexes are alike in plumage, rusty-brown on the back and crown with white to light gray unstreaked breasts.

The nests of this species, composed almost exclusively of grasses, are located near the ground in early spring but later are built in small saplings and shrubs as ground cover increases in height. Pairs renest rapidly following predation or desertion. Only females incubate eggs, but both sexes share roughly equally in the feeding of young. While adults are faithful to breeding sites, young rarely return to their natal area. Although by no means threatened, Field Sparrows appear to be declining in numbers, probably due to changes in their breeding habitat as shrubby old fields grow to forest or are cleared for agriculture or suburban growth.