The Lark Sparrow is a large (15 to 17 cm, 24.7 to 33.3 g), long-tailed sparrow with a distinctive alternating chestnut, black and white facial pattern, and towhee-like black tail with white corners, conspicuous in flight or perched. Plain whitish underparts with dark spot on center of breast. Adults with variable black streaking on upperparts, otherwise generally appearing brownish gray to buffy brown above with two pale buff to whitish wing bars. Sexes similar except that the male is slightly larger than the female. Its name infers the tonal quality of its lark-like song. Singing is most notable by males perched at height points in early morning, evening and even at night (Martin and Parrish 2000).
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
In the Bozeman, area normal migration periods are May 16 to 30 and early August to September 1.
Widespread in open habitats such as shrub-steppe, pinion-juniper edges, grasslands, roadsides, farmlands, and pastures (Martin and Parrish 2000).
Categorized as a ground-foraging omnivore during the breeding season, and a ground-gleaning granivore during the nonbreeding period. In breeding season, eats more insects than seeds. During colder periods, when insects are less readily available, seeds may be primary diet (Martin and Parrish 2000).
Nests on bare ground, in hollow depression, or in shrub or tree up to 2.75 m from ground. May use unusual nest sites such as a natural cavity of a dead tree. Eggs are short elliptical to subelliptical in shape. Color is overall white, cream or gray-white with markings. Clutch size ranges 3 to 6 eggs, with 4 eggs most common. Statewide, nests have been seen from early June through July.