Bachman's Sparrow

Aimophila aestivalis

(c) Ashok Khosla
  • EMBERIZINAE
  • Sparrows, Buntings, Towhees, Longspurs
  • Passeriformes
  • Zacatonero de Bachman
  • Bruant des pinèdes
Introduction

Shy and secretive, Bachman's Sparrow is usually difficult to see, but breeding males may sing from low and exposed perches in spring. This small songbird was formerly called the Pine-woods Sparrow, in recognition of its preferred habitat. Natural fire is the key to healthy pine woodlands, but fire suppression and both tree and row-crop farming now minimize the extent and quality of this ecosystem.

(c) Ashok Khosla
Appearance Description

With a stout bill and long, rounded tail, Bachman's Sparrow is a fairly large sparrow. It measures 5-6 inches long with a 7.2- inch wingspan and weighs up to 0.8 ounces. The upperparts present a complex pattern of gray streaks alternating with rusty-brown streaks, marked with black. The rump is gray and the upper tail dark brown. The crown, hind neck, and a stripe extending behind the eye are streaked with dark brown and rufous. The eyebrow is light gray, as are the face, throat and chest. The belly is whitish, and the underparts are unstreaked. The eye is dark brown, the bill gray, and the legs dull yellow.

Range Map
Courtesy Kenn Kaufman
Range Distribution

As southeastern pine woods continue to shrink or be altered by commercial farming, Bachman's Sparrow retreats south and east into forest fragments. Endemic to the United States, it breeds and winters from Arkansas south into East Texas and then eastward to the Carolinas and Florida. Christmas Bird Counts indicate a withdrawal from the northern part of the breeding range in winter. In the early 2000s, breeding appeared most dense in Florida and south-central Alabama. As Americans left their farms for cities at the turn of the 19th Century, Bachman's Sparrow occupied the re-growing pine forests, and its range expanded northward from southern Oklahoma to southwestern Pennsylvania. The expansion was largest between 1915 and 1920. Bachman's Sparrow is now practically absent from states like Illinois and Ohio.

Habitat

Primarily, Bachman's Sparrow occupies open pine woods with a grassy floor, but can sometimes use oak-palmetto scrub and open spaces that are in transition to forest (replanted clearcuts, powerline cuts, and abandoned fields). Important understory components include grasses (wiregrass, panic grass, little blue stem, broom sedge), palmetto, leaf litter, and open ground. Frequent and brief natural fire maintains this habitat best. Even fairly small patches (7-140 acres) of suitable habitat may be occupied. All of its closest relatives, like the Cassin's Sparrow, are grassland species.

Feeding

Walking and hoping on the ground, Bachman's Sparrow methodically searches the forest floor and leaf litter for seeds and insects. Food items are plucked from surfaces (gleaning) and snatched from the air in short hops. The diet appears to shift with the seasons. The insect diet includes beetles (many weevils), caterpillars, crickets, grasshoppers, leafhoppers, and wasps. This songbird consumes the seeds of grasses (panic and bristle), pines, sedges, and blueberries. Natural, frequent fire appears to increase the insect prey favored by the Bachman's Sparrow.

Reproduction

Monogamous pairs of Bachman's Sparrows probably form before territories are established in late March and early April, and they may be maintained for more than one season. Males sing vigorously from low, exposed perches, but territories may otherwise be poorly defended. Most pairs successfully raise two broods. Next to a tussock of grass or some other low vegetation, the female constructs a nest cup by herself in a scraped depression, usually covers it with a dome, and lines it with animal hair and fine grass pieces. Nests are made of grass parts, weed stems, and small roots.

The female incubates 3-5 whitish eggs for about 13 days, while the male keeps his distance and sings. The hatchlings are mostly naked, completely blind, and helpless. Both parents provision the young with small insects and remove fecal sacs from the nest, until the young fledge in about 10 days. Twenty-five days later, most juvenile Bachman's Sparrows leave the territory, and they attain adult size at about five weeks of age. The pair take a break, a little less than two weeks, before starting the second nest.

Migration

The migratory behavior, routes, and exact timing are poorly documented for Bachman's Sparrow. Southern populations apparently do not migrate. In the fall, northern populations probably migrate between late August and late October. For them, spring migration is fairly early, with first arrival dates ranging between late March and early April. Since this songbird has withdrawn from much of its northern range, the extent of its migration is now even more unclear.

  • 250,000
  • 250,000
Population Status Trends

This sparrow's population has risen and fallen considerably over the last 200 years, with a generally declining trend since the 1940s. After reaching high numbers in the early 20th Century, populations shrank dramatically, especially between the 1930s and 1960s. From 1966 to 2005, the Breeding Bird Survey recorded an average annual decline of 1.9%, with significant losses across its western and southern ranges. Where Bachman's Sparrow is most numerous, Florida saw a 3.1% annual loss for 1966-2005.

Conservation Issues

Except were it has been extirpated, every state within its range recognizes Bachman's Sparrow as a conservation concern at some level, notably: Georgia, Imperiled; Tennessee, Endangered; and Texas, Threatened. The loss and degradation of longleaf pine savannahs seems to be the primary causes of its decline. Of the almost 90 million acres of longleaf that spread across the south before European colonization, only 3% remain. Today, the Bachman's Sparrow's stronghold is in Florida, but here the pine woodlands continue to be cut for real-estate development and logging. In 1936, Florida had approximately 7.6 million acres of longleaf forests. By 1989, that forest had been reduced to 0.9 million acres, an 88% loss.

The good news is that Bachman's Sparrow can re-colonize abandoned parts of its range. Once a wasted tract of sand and scrub, the Carolina Sandhills National Wildlife Refuge, near McBee, South Carolina, is a good example of forest restoration. Here, the longleaf pines have been managed for the Endangered Red-cockaded Woodpecker, a conservation strategy that also benefits this sparrow. The key to fitting the habitat needs of these species together is fire. Without fire, the forest understory becomes thick with deciduous scrub, predators move in, grasses die and cannot provide seeds, and insect prey become scarce. Of its 42,000 forested acres, the Carolina Sandhills N.W.R. burns at least 12,000 acres each year.

In Florida alone, an estimated 165,432 acres of publically owned mixed pine/oak forest was available for longleaf restoration in 1995, and another 197,530 acres was in private hands. To enlist the help of private landowners, the Conservation Reserve Program, state outreach programs like North Carolina's CURE, and private conservation groups like the Longleaf Alliance provide affordable tree stock, free seed (wild grasses and forbs), conduct workshops and demonstrations, offer management brochures, and channel fiscal incentives for conservation projects to benefit the longleaf forest, Red-cockaded Woodpecker, and Bachman's Sparrow.

What You Can Do

Look for Bachman's Sparrow in late spring or early summer, when males are singing. Your local bird club may have a trip dedicated to longleaf pine specialists. You can also look for them in the Carolina Sandhills National Wildlife Refuge, near McBee, South Carolina 

If you own land that supports or has the potential for supporting Bachman's Sparrow, consider managing it in ways that would increase numbers of the species. Contact your state wildlife agency or your state Audubon office for more details.

Audubon's Important Bird Area program is a vital tool for the conservation of Bachman's Sparrow as well as other species. To learn more about the Important Bird Areas program and how you can help. 

Find out about actions you can take including Audubon programs and activities.

More Information

The U.S. Forest Service has a useful fact sheet on the Longleaf Pine Ecosystem.

Learn more about this species and other birds through these resources

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Natural History References

Dunning, J. B. Bachman's Sparrow. (Aimophila aestivalis). The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Laboratory of Ornithology, 2006. Accessed 16 June 2007. 

Meyer, Rachelle. "Aimophila aestivalis." Fire Effects Information System [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory: 2006. Accessed 18 June 2007.

Rising, J. 1996. A Guide to the Identification and Natural History of the Sparrows of the United States and Canada. Academic Press, San Diego, CA.

Conservation Status References

Dunning, J. B. Bachman's Sparrow. (Aimophila aestivalis). The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Laboratory of Ornithology, 2006. Accessed 16 June 2007.

Dodd, Kenneth C. Jr. "Reptiles and Amphibians in the Endangered Longleaf Pine Ecosystem."
Our Living Resources: National Biological Service A Report to the Nation on the Distribution, Abundance, and Health of U.S. Plants, Animals, and Ecosystems. 1995. U.S. Department of the Interior, National biological Service. Accessed 18 June 2007.

Meyer, Rachelle. "Aimophila aestivalis." Fire Effects Information System [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory: 2006. Accessed 18 June 2007.

Outcalt, Kenneth W. "Needs and Opportunities for Longleaf Pine Ecosystem Restoration in Florida." Longleaf Alliance Report No.3. Proceedings of the Longleaf Pine Ecosystem Restoration Symposium (Nov. 12-15) 1997: 38-43. Accessed 18 June 2007.

Sauer, J. R., J. E. Hines, and J. Fallon. 2005. The North American Breeding Bird Survey, Results and Analysis 1966 - 2005. Version 6.2.2006. USGS Patuxent Wildlife Research Center, Laurel, MD. Accessed 16 June 2007.