Introduction

The Lark Sparrow is a widespread breeding species of open habitats such as shrub-steppe, piñon-juniper edges, grasslands, roadsides, farmlands, and pastures. Although it formerly bred as far east as the northern and central Atlantic states, its breeding range is now receding, probably toward its original pre-Columbian distribution as eastern lands historically cleared for agriculture during the mid-1800s return to forest, or are progressively taken over by urbanization.

This large, long-tailed sparrow has a distinctive alternating chestnut, black, and white facial pattern, and towhee-like black tail with white corners, conspicuous in flight or perched. Its name infers the tonal quality of its lark-like song. Singing is most notable by males perched at high points within territories and, at times, on the ground or in flight, in early morning, evening, and even at night.

Courtship in this species differs markedly from that of other passerines. Males perform turkey-like strutting with tail upright, flashing white tail spots, and wings dropped to the ground. Unique to the Lark Sparrow is the behavior of passing a twig from male to female during copulation, which may be an alteration of courtship feeding observed in other species. Breeding females are known to use nests, generally abandoned ones, of other species.

The Lark Sparrow shows a preference for ecotones between grassland or shrub and forested habitat types, often including disturbed sites with exposed soils, grazing or recent fire, and fallow fields. Due to its preference for edge habitats, this species appears to have been excluded from some of the thorough avian community studies in grasslands (US/IBP BIOME studies) and shrub-steppe (Wiens, Rotenberry, and others [Wiens and Rotenberry 1979, Rotenberry 1980, Rotenberry and Wiens 1980, Wiens and Rotenberry 1981]) during the 1970s and 1980s. To date there are no definitive studies of the Lark Sparrow.