Spizella pusilla
field sparrow

Field sparrows are found throughout the eastern United States from just east of the Rocky Mountains to the Atlantic Coast and from North Dakota to southern Texas in the west and New Hampshire to Florida in the east. They are also found in southern Ontario and southernmost Quebec. Their breeding and wintering ranges overlap substantially and they are found year-round throughout much of their range except for the northernmost and southernmost portions. Some populations are resident year-round while others undertake short migrations. (Carey, Burhans, and Nelson, 2008)

Field sparrows can be common in preferred habitat, but are rarely found near human habitation, even in appropriate habitat. They are found in open, savanna-like habitats, such as successional old fields, forest edges and openings, fencerows and road or railway cuts near open fields, and occasional orchards and nurseries. They are found only in fields with some trees or shrubs that provide perches. Once succesional habitats become overgrown with trees and shrubs, field sparrows are no longer found there. (Carey, Burhans, and Nelson, 2008)

Male field sparrows are slightly larger than females, but both sexes have similar plumage. They are reddish brown on their heads and back with gray, un-streaked bellies. They have two white wing bands, a white eye ring, and a rusty brown stripe extending from the eye. Their bill and legs are pinkish, helping to distinguish them from other sparrows. They might be confused with Worthen's sparrows (Spizella wortheni) in southern New Mexico, but they lack the rufous stripe from the eye, a different song, and black legs. (Carey, Burhans, and Nelson, 2008)

Maximum recorded age in the wild is 8 years 9 months, based on banding records. Annual male survivorship is estimated at 53% and annual female survivorship at 36%. Winter range conditions may result in higher mortality. Approximately 50% of fledglings are thought to die before the fall of their hatch year. (Carey, Burhans, and Nelson, 2008)

Field sparrows are found in territorial, mated pairs during the breeding season and in small flocks during the winter and migration. Breeding territories are established with song and perhaps some male-male aggression, but field sparrows are generally reported to be non-aggressive. They forage mainly on the ground, hopping along to discover seeds, and sleep on perches in woody vegetation. Some populations undertake small migrations but other populations remain resident year-round. (Carey, Burhans, and Nelson, 2008)

Home Range

Breeding territory sizes were estimated at an average 0.76 ha (range 0.31 to 1.62 ha) in one population. (Carey, Burhans, and Nelson, 2008)

Field sparrows are recognized by their distinctive, pretty song, consisting of soft whistles that accelerate towards a trill. Males use songs to advertise territories during the breeding season. Young field sparrows learn songs from their parents. Field sparrows also have a repertoire of other calls, including a foraging note ("seep"), courtship calls, trill calls used in territorial defense and courtship, cricket calls used by females at the nest, chip calls given in the presence of a threat, and "zeeee" or "eeeee" calls used with threats. (Carey, Burhans, and Nelson, 2008)

Field sparrows take seeds, primarily grass seeds, throughout the year. Grass seeds make up less than 50% of their diet in the summer, but more than 90% in the winter. In the summer, breeding season they also take adult and larval insects and spiders. They forage on the ground, most often near some form of vegetative cover. In the breeding season field sparrows forage on their own or with a mate, but they form small foraging flocks in winter. They take fallen seeds or land on grass stems and push them to the ground, where they remove the seeds. They use perches to briefly scan for insect prey. (Carey, Burhans, and Nelson, 2008; NatureServe Explorer, 2008)

Observed predators of eggs and nestlings include chipmunks (Tamias striatus) and many species of snakes (Elaphe obsoleta, Coluber constrictor, Lampropeltis, Thamnophis sirtalis, Lampropeltis calligaster). The most common predators recorded are black rat snakes (Elaphe obsoleta). Likely predators include red foxes (Vulpes vulpes), grey foxes (Urocyon cineoargenteus), weasels (Mustela), mink (Neovison vison), skunks (Mephitis mephitis), raccoons (Procyon lotor), and opossums (Didelphis virginianus). Field sparrows use a "chip" call to alert others to a threat. They will use a broken-wing display to distract predators from their nest. (Carey, Burhans, and Nelson, 2008)

Many kinds of ectoparasites are found on field sparrows, including feather mites. They are also infected by Plasmodium species. Field sparrows are important predators of grass seeds in their savanna and edge habitats. Nests are parasitized by brown-headed cowbirds (Molothrus ater), although frequency varies regionally. Most parasitized nests are deserted by the female. If a field sparrow nest is successfully parasitized by brown-headed cowbirds, their overall nesting success is greatly reduced and few of the cowbird nestlings are successfully raised. (Carey, Burhans, and Nelson, 2008)

There are no adverse effects of field sparrows on humans.

There are no direct positive impacts of field sparrows on humans. They are an interesting member of the native, North American bird fauna and are appreciated for their song. (Carey, Burhans, and Nelson, 2008)

Field sparrows are sensitive to habitat disturbance and have fairly narrow habitat preferences. They are not found in areas with human habitations, which are expanding currently. Available habitat may increase in areas with recent forest cutting, or decrease in areas with predominantly successional habitats, which become inappropriate for field sparrows as they grow. Populations have experienced declines across their range, but field sparrows are widespread and fairly common where habitat is appropriate, so they are not considered threatened currently. However, populations in Colorado are considered critically imperiled and populations in New Hampshire, Massachusets, Maine, Quebec, and the Canadian maritime provinces are considered vulnerable. (Carey, Burhans, and Nelson, 2008; NatureServe Explorer, 2008)