Aimophila aestivalis
Bachman's sparrow
(Also: Bachman's sparrow)

Bachman's sparrows are found in the southeastern United States. Most of the populations live in Florida and along the Gulf Coast. They are also found as far north as the Indiana-Michigan border and as far west as the Arkansas-Oklahoma border. In the winter, Bachman's sparrows are especially secretive and little is known of their winter habits. Their winter range seems to be compressed into the coastal southeastern U.S., Florida, the Gulf states, and eastern Texas. (Dunning, 1993; USGS, 2010)

Bachman's sparrows are mostly found in open oak and pine forests with abundant grasses. They are most often found in forests with wiregrass (Aristida) or broomsedge (Andropogon). Populations are highest in areas where forest fires are regular, eliminating hardwood understory shrubs. Bachman's sparrow populations disappear 4 to 5 years after a burn. Much of their original habitat, open pine forests, has been logged throughout their range, forcing them into marginal habitats, such as forest edges and utility rights-of-way, where hardwood understory shrubs are discouraged by poor soils, fires, or human management. (Dunning, 1993; Missouri Dept. of Conservation, 2009)

Bachman's sparrows are relatively small in size and plain brown in color with reddish streaks. They have cone shaped bills and pale brown faces. Bachman's sparrows have long brown tails with reddish brown backs. The breast is pale white in color. Bachman's sparrows also have a brownish-red crown. They are 12.2 to 15.2 cm long and about 21 grams in weight. They may be confused with a related species, Aimophila botterii in southeastern Texas, where their ranges overlap. However A. botterii is found in grasslands. They may also be confused with field sparrows (Spizella pusilla), which have smaller bills and tails, a white eye ring, less color on the face, and two white wing bars. ("Species Profile: Bachman's Sparrow (Aimophila aestivalis) on Military Installations in the Southeastern United States", 1998; Dunning, 1993; Missouri Dept. of Conservation, 2009; The Georgia Museum of Natural History and Georgia Department of Natural Resources, 2006)

There is little available information on longevity in Bachmann's sparrows. Studies have shown survival into their third and fourth years. (Max Planck Institute, 2002)

Bachman's sparrows have been observed hiding in the burrows of other animals. The suspected reason for this is for protection from predators. Bachman's sparrows are active during the day. Northern populations seem to be migratory, migrating to warmer areas in the coastal southeastern U.S.. Southern populations seem to be resident. Little is known about the migration of these birds. Bachman's sparrows are active during the day, during the breeding season they forage mostly during the first 5 hours of the day and 2 hours before sunset. Bachman's sparrows are mainly active on the ground. When disturbed they often drop from flight and run on the ground to escape. Their flight is described as weak and "floppy" as their tail pumps during flight. (Dean and Vickery, 2003; Dunning, 1993)

Home Range

Breeding territories range in size from 0.62 to 5.1 hectares. (Dunning, 1993; The Georgia Museum of Natural History and Georgia Department of Natural Resources, 2006)

Bachman's sparrows use songs and calls to communicate with conspecifics. Vocalizations are sometimes the most reliable way of distinguishing among sparrow species. Bachman's sparrows have 3 main songs, used by mails to attract females for breeding: primary songs, whisper songs, and excited songs. The primary song is described as one of the most beautiful sparrows songs. Both males and females use "calls", which include "chip", "pseet", "chitters", used in mate recognition and aggression, and others. (Dunning, 1993)

Bachman's sparrows are omnivorous, eating mainly insects and seeds. The feed on the ground. Insects consumed include beetles, bugs, grasshoppers, crickets, millipedes, and spiders. They also eat the seeds of grasses, especially Panicum species, sedges, and wood sorrel. ("Species Profile: Bachman's Sparrow (Aimophila aestivalis) on Military Installations in the Southeastern United States", 1998; USGS, 2010)

Predation on adult Bachman's sparrows is not documented. Known predators of Bachman's sparrow nestlings and eggs include crows and snakes, especially Coluber species and Elaphe species. In one study 12% of all Bachman's sparrows eggs were eaten by snakes. Brown-headed cowbird nestlings will often directly or indirectly kill Bachman's sparrow nestlings when they parasitize their nests. Adult Bachman's sparrows will feign an injury to distract predators near their nests. (Dunning, 1993)

There is little known about the role of Bachman's sparrows in the ecosystem. One can speculate that they aid in seed dispersal through seed eating and that they help to control insect populations. They are parasitized by brown-headed cowbirds (Molothrus ater) who lay their eggs in Bachman's sparrow nests. Bachman's sparrows seem to rely on similar habitats to those required by red-cockaded woodpeckers (Picoides borealis). (Dunning, 1993)

Several ectoparasites are known from Bachman's sparrows: Analgopsis mites, the tick Haemaphysalis leporis-palustris, and lice in the genus Ricinus. Blowfly larvae (Protocalliphora deceptor) are known from nests. (Dunning, 1993)

Bachman's sparrows are not harmful to humans. (Missouri Dept. of Conservation, 2009)

Bachman's sparrows have no direct effect on humans. One could argue that they play a key role in the food chain, in that they eat insects and other arthropods and keep their population down. (Missouri Dept. of Conservation, 2009)

The main threat to Bachman's sparrows is the elimination of the open pine forest habitat on which they rely. Since they nest on the ground, they are especially vulnerable. On the IUCN Red List they are listed as low risk. But they are protected under the Migratory Bird Act. They are given no special status on the US Federal List and CITES. In Tennessee Bachman's sparrows are listed as endangered, they are threatened in North Carolina, Oklahoma, and Kentucky. Bachman's sparrows are relatively rare, because of this there is not a lot known about this species. Bachman's sparrows rely on similar habitats to those required by red-cockaded woodpeckers (Picoides borealis). The protection of open pine forests throughout the southeastern United States has impacted populations of both rare bird species. (Dunning, 1993; Missouri Dept. of Conservation, 2009; The Georgia Museum of Natural History and Georgia Department of Natural Resources, 2006)