Bachman's Sparrow, Peucaea aestivalis, is a small American sparrow

American sparrow

American sparrows are a group of mainly New World passerine birds, forming part of the family Emberizidae. American sparrows are seed-eating birds with conical bills, brown or gray in color, and many species have distinctive head patterns....

 that is endemic to the southeastern United States

Southeastern United States

The Southeastern United States, colloquially referred to as the Southeast, is the eastern portion of the Southern United States. It is one of the most populous regions in the United States of America....

. This species was named in honor of Reverend John Bachman

John Bachman

The Rev. John Bachman was an American Lutheran minister, social activist and naturalist who collaborated with J.J. Audubon to produce Viviparous Quadrapeds of North America and whose writings, particularly Unity of the Human Race, were influential in the development of the theory of evolution. He...

.

Adults have rufous brown upperparts and crown with grey and black streaking on the nape, back and primaries. The face is gray with a rufous brown eyestripe. It has buff colored breast and whitish belly.

Their breeding habitat is open pine

Pine

Pines are trees in the genus Pinus ,in the family Pinaceae. They make up the monotypic subfamily Pinoideae. There are about 115 species of pine, although different authorities accept between 105 and 125 species.-Etymology:...

 forests. The domed nest is usually built on the ground near a clump of grass or a bush. Females lay 3–5 eggs.

Bachman's Sparrow is primarily a non-migratory resident, but it may retreat from some of the most northerly territories. The species is mainly a granivore

Seed predation

Seed predation, often referred to as granivory, is a type of plant-animal interaction in which granivores feed on the seeds of plants as a main or exclusive food source, in many cases leaving the seeds damaged and not viable...

, but it will also take some insect

Insect

Insects are a class of living creatures within the arthropods that have a chitinous exoskeleton, a three-part body , three pairs of jointed legs, compound eyes, and two antennae...

s.

This bird is considered Near Threatened

Near Threatened

Near Threatened is a conservation status assigned to species or lower taxa that may be considered threatened with extinction in the near future, although it does not currently qualify for the threatened status...

, with habitat loss one of the major factors often cited in its decline. Habitat degradation due to later stages of forest succession

Ecological succession

Ecological succession, is the phenomenon or process by which a community progressively transforms itself until a stable community is formed. It is a fundamental concept in ecology, and refers to more or less predictable and orderly changes in the composition or structure of an ecological community...

 has also been attributed to the decline of this species. Prescribed forest burns

Controlled burn

Controlled or prescribed burning, also known as hazard reduction burning or Swailing is a technique sometimes used in forest management, farming, prairie restoration or greenhouse gas abatement. Fire is a natural part of both forest and grassland ecology and controlled fire can be a tool for...

 may assist in recovery.

The song begins as a clear whistle, followed by a short trill.

Distribution

According to literature reviews, Bachman's sparrows occur primarily in the southeastern United States from the central region of peninsular Florida north to limited areas of extreme southern Virginia and west through portions of Tennessee, Kentucky and Missouri to eastern Oklahoma and eastern Texas . Bachman's sparrows may rarely occur in more northerly areas that were part of their historic breeding range, including most of Illinois, Indiana, Ohio, West Virginia and parts of Pennsylvania and Maryland .

Reviews also describe the range of the 3 subspecies of Bachman's sparrow. Peucaea aestivalis aestivalis breeds furthest east, from southeast South Carolina to peninsular Florida. Peucaea a. bachmanii occurs west of P. a. aestivalis to Mississippi and north to Kentucky. P. a. illinoensis occurs in the westernmost region of the species' range .

Migration

Reviews and a field guide summarize the limited information available on Bachman's sparrow migration . Bachman's sparrows in the southern portion of the range are resident, while those in Missouri, Arkansas, eastern Oklahoma, Tennessee, Virginia, parts of North Carolina, and extreme northern Mississippi and Alabama migrate south during winter . Due to their secretive nature in winter, determining the presence of Bachman's sparrows is difficult. However, records of Bachman's sparrow occurrence on breeding grounds and specimens of subspecies collected outside their normal breeding range suggest that spring migration occurs from mid-March to May and fall migration occurs from late August through to late October .

Breeding

Bachman's sparrows' breeding season typically begins in April and continues through August. According to a literature review the earliest date for Bachman's sparrow eggs in Florida is 14 April and the latest date is 4 August . The earliest Bachman's sparrow nest found during a study in longleaf pine habitat of South Carolina was 10 April, while the latest nest found was early in the incubation stage on 5 August . In a study of Bachman's sparrow reproduction in shortleaf and loblolly pine plantations of Arkansas, egg laying started as early as 17 April and continued until 26 August. However, 85% of clutches were started in May, June, or July . A review summarizes the timing of Bachman's sparrow nest construction and egg-laying, including records from more northern areas in the Bachman's sparrow's historic range .

Bachman's sparrows typically raise 2 broods per breeding season and will renest after failed attempts . In shortleaf and loblolly pine plantations of Arkansas, the average time between fledging of the 1st brood and starting the 2nd brood was 12.3 days. This was not significantly (p=0.39) different than the 9.7-day average period between a failed nest and a subsequent nest attempt. On average, females attempted 3.1 nests per season. The maximum number of attempts per season was 5 . The maximum number of nests attempted in longleaf pine habitat of South Carolina was also 5. After 2 successful nests, a female attempted 3 times to raise a 3rd brood . Limited evidence, summarized in reviews, suggests that 3 broods per season may occur occasionally . Dates of possible 2nd broods are included in one of these reviews .

Bachman's sparrow nests are constructed on the ground by females and are primarily made of grasses. All nests (n=71) found in a study in shortleaf and loblolly pine plantations of Arkansas were built on the ground. Most nests (70%) were built at the base of bluestem clumps, although nests were found at the base of small trees, forbs, and other grass species . On the same study site, only 7% of nests were not either partially or completely domed. Most nest entrances were oriented to the north . Several reviews summarize information on nest construction

According to reviews, clutch size varies from 3 to 5 . Average clutch size on a site in Arkansas was 3.9 , while in a longleaf pine community in South Carolina mean clutch size was 3.6 . Both of these studies found significant (p≤0.02) decreases in clutch size as the breeding season progressed . On a dry prairie site in Florida (n=9) average clutch size was 3.44 and on another (n=5) it was 3.6 . In shortleaf and loblolly pine plantations of Arkansas, females laid an average of 11.6 eggs (n=20) over the course of the breeding season .

In shortleaf and loblolly pine plantations in Arkansas, females incubated eggs for 13 to 14 days. The average nestling period was 9 days, and the average period between fledging and independence was 25 days. Both parents care for the young during these periods . Although there is a lack of data, a review suggests that Bachman's sparrows probably breed the year after hatching .

Bachman's sparrows exhibit some fidelity to breeding sites. Over a 2 year period in shortleaf and loblolly pine plantations of central Arkansas, 6 of 34 adults returned to areas where they had a territory in a previous year. This varied across years, with a 29% return rate of adult birds banded in 1983 and none of the adults banded in 1984 returning to the site in 1985. No juveniles (n=60) returned to the site .

Nesting success

Values of nest success reported for Bachman's sparrows vary. Daily nest survival rate of Bachman's sparrow ranged from 0.89 to 0.96 across sites and years in the dry prairie of central Florida. On average 3.13 birds were fledged per successful Bachman's sparrow nest. Estimates of productivity ranged from 1.21 to 4.16 offspring per pair per year across sites and years . In a South Carolina longleaf pine community, daily survival rate of Bachman's sparrow nests in 1995 was 0.952, which was significantly (p=0.04) higher than the 1996 daily nest survival rate of 0.889. Earlier nesting attempts (before June 15, n=15) had significantly (p=0.05) higher survival rates than those started later in the year (n=11). Daily nest survival rate was 0.922 during incubation and 0.973 during the nestling stage . In central Arkansas, daily success rate during the incubation period was 0.965, while in the nestling period it was 0.919 . In the glades of south-central Missouri, 8 female Bachman's sparrows fledged an average of 1.5 young per season over 2 years . Predation accounted for 80% of egg loss on study sites in Arkansas and 94% of nest failures on sites in central Florida . Information on Bachman sparrow nest predators can be found in the Predators section of this summary. Cowbirds and nest abandonment were the other known causes of nest failure.

Survival

Survival of Bachman's sparrows during the breeding season has been investigated in a South Carolina study area dominated by longleaf pine . Recapture of banded birds resulted in a monthly survival rate during the breeding season of 0.94 . Using radio telemetry, average survival of Bachman's sparrows from 20 April to 26 July was 80.0%. In another radio telemetry study, 4 mortalities out of 38 Bachman's sparrows were documented over 2 years. The overall breeding season survival rate was estimated as 0.893 . According to a literature review, Bachman's sparrows have been captured that were at least 3 years old .

Preferred habitat

Bachman's sparrows inhabit areas with a dense layer of ground vegetation and open mid-stories with scattered shrubs and saplings, including young clearcuts and open pine (Pinus spp.) forests 66.

Habitat characteristics

Bachman's sparrows' need of a dense layer of herbaceous vegetation is widely documented. Vegetation density was greater below 3 feet (0.9 m) than above 3 feet (0.9 m) and percent ground cover and percent grass cover were consistently higher (>58%) on sites occupied by Bachman's sparrow than unoccupied sites in Arkansas, Alabama, Florida, South Carolina and North Carolina . In 17- to 28-year- old slash pine plantations of northwestern Florida that had been burned within 4 years, Bachman's sparrow abundance was significantly (p=0.043) correlated (r=0.46) with relative volume of grass [66]. In longleaf and loblolly pine stands of varying ages and under different management in South Carolina, areas occupied by Bachman's sparrows consistently had high vegetation volumes ≤3 feet (1 m) above ground . Sites occupied by Bachman's sparrows in longleaf pine woodlands of Florida managed for the red-cockaded woodpecker (Picoides borealis) had significantly (p=0.007) higher vegetation densities ≤ 2 feet (0.5 m) than unoccupied sites in the study area. Grass density, primarily bluestems (Andropogon spp. and Schizachyrium spp.) ≤ 2 feet (0.5 m) above ground, was also significantly (p=0.004) greater on occupied compared to unoccupied sites . Bachman's sparrows were significantly (p≤0.01) more abundant in mixed pine-grassland restoration stands in Mississippi, which had greater understory, grass, and forb cover, than traditionally managed stands . In 1- to 6-year-old loblolly pine stands of eastern Texas, herbaceous ground cover (p=0.003) was greater in study areas occupied by Bachman's sparrows . In south-central Missouri, glades occupied by Bachman's sparrows had significantly more grass (p=0.03) and forb cover (p=0.0005) than unoccupied glades . However, vegetation densities below 3 feet (0.9 m) and percent ground and grass cover in areas occupied by Bachman's sparrow did not differ significantly (p>0.05) from unoccupied areas of loblolly and shortleaf pine plantations in Arkansas .

Factors such as the patchiness of vegetation and species composition of the ground layer may affect habitat suitability by influencing foraging success and the availability of food and nesting material. In Georgia, Bachman's sparrows did not occur in open areas with uniformly dense herbaceous vegetation, despite these sites having a similar volume of vegetation ≤3 feet (1 m) above ground as recently-burned pineland sites that were occupied by Bachman's sparrow . Although measurements were not taken, observations of Bachman's sparrow in clearcuts in eastern Texas suggest they may favor tall grass in clumpy rather that uniform distribution . In loblolly and shortleaf pine plantations of Arkansas, explanations suggested for a lack of evidence of ground layer features influencing selection of breeding territories included importance of habitat characteristics that were not measured, such as patchiness of the herbaceous layer and species composition . In a predominantly longleaf pine forest in Georgia, Bachman's sparrows were significantly (p=0.04) more abundant in areas where ground cover was primarily Beyrich threeawn (Aristida beyrichiana), compared to relatively disturbed communities of bluestems (Andropogon spp.) and silkgrass (Pityopsis spp.) .

Amount of litter and debris on a site may influence Bachman's sparrow habitat selection. Percent litter cover was consistently high (>58%) on sites occupied by Bachman's sparrow in Arkansas, Alabama, Florida, South Carolina and North Carolina . Although statistical significance was not tested due to small sample size, Bachman's sparrows occurred at higher densities in control plots (1.5 territories/40 ha) than plots that had downed coarse woody debris

Coarse woody debris

Coarse woody debris is a term used in English-speaking countries for fallen dead trees and the remains of large branches on the ground in forests. Some prefer the term coarse woody habitat . A dead standing tree is known as a snag and provides many of the same functions as coarse woody debris...

 >4 inches (10 cm) in diameter removed (0.4 territories/40 ha) in a loblolly pine forest of South Carolina. Haggerty suggests that litter may provide habitat for Bachman's sparrow prey, but that too much litter could interfere with foraging. In loblolly and shortleaf pine plantations of Arkansas, litter cover (78%) and depth (0.5 inches (1.2 cm) on sites occupied by Bachman's sparrows were significantly (p≤0.01) lower than litter cover (88.9%) and depth (1.6 inches (4.2 cm)) on unoccupied sites .

Bachman's sparrow inhabits areas with open overstories. In sites in eastern Texas of varying age since clearcutting, study areas occupied by Bachman's sparrows had significantly (p<0.01) fewer short (≤ 10 feet (3m)) and tall (>10 feet (3m)) trees than unoccupied study areas . In longleaf and loblolly pine stands of varying ages and under different management in South Carolina, plots occupied by Bachman's sparrows consistently had low volumes of vegetation from 7 to 13 feet (2–4 m) above ground compared to unoccupied sites . In middle-aged and mature forests of Georgia composed primarily of loblolly pine, Bachman sparrow densities were negatively associated with tree/shrub volume and vegetation volume from 7 to <16 feet (3 to <5 m) . In loblolly and shortleaf pine plantations of Arkansas, Bachman's sparrow breeding areas had significantly lower percent canopy cover (p<0.001), shorter woody vegetation (p≤0.01) and fewer trees (p<0.001) and shrubs (p≤0.05) than unoccupied sites . In south-central Missouri, Bachman's sparrows occurred in glades with less than 30% woody cover, and occupied glades had significantly (p≤0.05) lower percentages of deciduous and coniferous saplings, deciduous and coniferous trees, and total woody vegetation . Mid-story density was marginally (p=0.055) greater on unoccupied sites, and Bachman's sparrow abundance was significantly (p=0.043) negatively correlated (r= –0.446) with mid-story density in longleaf pine woodlands of northwestern Florida. However, relative abundance of Bachman's sparrows was not significantly (p=0.107) associated with canopy cover and there were no significant (p=0.133) differences in canopy cover between occupied and unoccupied sites .

There is evidence that Bachman sparrow may prefer sites with some tall vegetation. In north-central Florida, densities of Bachman's sparrows in young (2–4 years) slash pine plantations with artificial snags added (n=3) was 31.4 pairs/km², while in similar vegetation without snags (n=3) Bachman's sparrow density was 22.3 pairs/km² [8]. In an area in South Carolina composed of longleaf and loblolly pine, Bachman's sparrow occurred at significantly (p=0.002) higher density in clearcuts than middle-aged (22–50 years) stands, while in another area clearcuts had relatively low densities of Bachman's sparrows. Vegetation differences between the 2 sites are likely to explain the difference. The site with relatively low densities of Bachman's sparrows had been drumchopped, which resulted in a lower volume of vegetation from 3 to 7 feet (1–2 m) above ground. The authors suggest that the lack of vegetation in this height range may have limited perches, resulting in fewer birds on the site . An investigation of Bachman's sparrow habitat characteristics in 1- to 6-year-old loblolly pine stands of eastern Texas led to recommendations that 2 to 5 tall (>39 feet (12 m)) trees/100 ha remain on a clearcut for Bachman sparrow singing perches . In Georgia, the lack of vegetation from 10 to <16 feet (3 to <5 m) was suggested as a possible reason for the absence of Bachman's sparrows from open field vegetation . However, across the southeast, vegetation density from 3 to 6 feet (0.91–1.8 m) above ground varies widely on sites occupied by Bachman's sparrows, suggesting their requirements for the density of this vegetation layer are comparatively flexible .

In the dry prairie of central Florida, Bachman's sparrows used clumps of saw-palmetto that had "natural" burrows significantly (p<0.001) more than would be expected based on availability. The authors suggest that Bachman's sparrows in prairie habitat use burrows as areas of refuge from predators .

Landscape level effects

Several studies have investigated the importance of landscape attributes on Bachman's sparrows. For a discussion of the possible importance of patchiness of vegetation within a site see the habitat characteristics section.

The ability of the Bachman's sparrow to detect and colonize areas before they are no longer suitable may depend on the size and isolation of the habitat. In south-central Missouri, only glades ≥ 29 acres (11.7 ha) were occupied by Bachman's sparrows . The probability of Bachman's sparrow occupying pine-grassland restoration stands in Mississippi increased as size of areas with long burning rotations, short-harvest rotations, and no removal of hardwoods decreased (p=0.05) and as the perimeter to area ratio of these areas increased (p=0.02) . In South Carolina, distance from source populations significantly (p≤ 0.05) influenced the ability of Bachman's sparrows to colonize recent clearcuts in both years on one study area and in 1 of 2 years in another study area. The authors suggest that the presence of corridors in the latter study area may have resulted in distance being less influential .

Bachman's sparrows' association with edge habitat is uncertain. In eastern Texas clearcuts with relatively abundant loblolly pine, sites with Bachman's sparrow territories were significantly (p<0.01) closer to the edge of the study area and the number of Bachman's sparrows was significantly (p<0.05) correlated (r=–0.22) with distance to edge . However, in dry prairie of central Florida the difference in Bachman's sparrow densities in edge and core habitat was not significant (p≥0.36), and both edge and core habitat were considered population sinks .

Territory and density

Territory size of Bachman's sparrows varies. In Missouri glades, reports of average Bachman's sparrow breeding territory range from 1.5 acres (0.62 ha, n=13) to 7 acres (2.9 ha, n=7) . In loblolly and shortleaf pine plantations of central Arkansas, mean home range size (n=25) during the breeding season was 6 acres (2.5 ha) . In on a south-central Florida site with saw palmetto and scrub palmetto (Sabal etonia) interspersed amongst threeawn (Aristida spp.), Bachman's sparrow territories (n=6) averaged 12.5 acres (5.1 ha). In winter (November-January), the average home range size of 8 Bachman's sparrows was 1.6 acres (0.65 ha) in the dry prairie of central Florida .

Bachman's sparrow density during in the breeding season has been estimated in several habitats. On clearcuts of various ages with relatively abundant loblolly pine in eastern Texas, maximum Bachman sparrow density was 1.9/10 ha . In South Carolina, Bachman's sparrow densities ranged from 0 to 0.48/ha across sites of different ages and management regimes . In Georgia, Bachman sparrow densities ranged from 0 to 0.92 birds/ha on sites ranging from an open field to middle-aged and mature forests composed primarily of loblolly pine . In a south-central Florida community composed of saw palmetto, scrub palmetto, and threeawn, Bachman's sparrow density averaged 1 male/33 ha. In dry prairie of central Florida, Bachman's sparrow densities varied from 0.92 to 3.24 territories/10 ha across sites and years . Bachman's sparrow densities calculated from breeding bird censuses in longleaf pine forests was >15 territories/40 ha, while densities from winter bird population studies were from 6 to 10 individuals/40 ha .

Food habits

Bachman's sparrows forage on the ground for plant seeds and arthropods. In a predominately loblolly and shortleaf pine habitat of eastern Texas, all Bachman's sparrow foraging observations were on the ground and a literature review states that Bachman's sparrows rarely forage in shrubs .

Reviews and an investigation of the Bachman sparrow's diet in eastern Texas summarize the species that comprise the Bachman's sparrow's diet. A variety of grass seeds such as panicgrasses, bristlegrasses (Setaria sp.), crowngrasses (Paspalum spp.), and threeawns are eaten by Bachman's sparrows as well as seeds of several other taxa, including blueberries (Vaccinium spp), pines, and sedges (Carex spp). Arthropods in the Bachman's sparrow's diet include grasshoppers and crickets (Orthoptera spp.), spiders (Araneae), beetles (Coleoptera spp.), caterpillars (Lepidoptera spp.), wasps (Hymenoptera), and leafhoppers (Cicadellidae) . According to reviews, insects comprise more of the Bachman's sparrow diet in spring and fall than in winter . Stomach contents of Bachman's sparrow collected in eastern Texas in summer (n=5) and fall (n=11) had a greater abundance of insects than those collected in winter (n=4) .

Predators

Data demonstrating which species prey on Bachman's sparrow are lacking. However short-tailed hawks (Buteo brachyurus) [48] and possibly American kestrels (Falco sparverius) prey on adult Bachman's sparrows. Species responsible for nest predation are not generally known . Evidence in 2 studies suggest mammalian predators and snakes eat Bachman's sparrow nestlings .

Bachman's sparrow nests are occasionally parasitized by brown-headed cowbirds (Molothrus ater) . In shortleaf and loblolly pine plantations of central Arkansas, 5% of 38 nest failures were due to brown-headed cowbird parasitism .

External links

• National Audubon Watch List species account
• Bachman's Sparrow videos on the Internet Bird Collection
• Stamps (for United States
  United States
  The United States of America is a federal constitutional republic comprising fifty states and a federal district...
  
  )
• Bachman's Sparrow photo gallery VIREO
• Bachman's (or Pinewoods) Sparrow Bird Sound

Books

• Dunning, J. B. (2006). Bachman’s Sparrow (Aimophila aestivalis). The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Laboratory of Ornithology; Retrieved from The Birds of North American Online database

Theses

• Allen RJ. M.S. (2004). Bachman's sparrow (Aimophila aestivalis) habitat in the western extent of its range. Stephen F. Austin State University, United States, Texas.

• Haggerty TM. Ph.D. (1986). REPRODUCTIVE ECOLOGY OF BACHMAN'S SPARROW (AIMOPHILA AESTIVALIS) IN CENTRAL ARKANSAS. University of Arkansas, United States, Arkansas.

• Laterza KJ. M.S.F. (1999). Effects of prescribed burning frequency on avian communities in a longleaf pine ecosystem. Stephen F. Austin State University, United States, Texas.

• Liu J. Ph.D. (1992). ECOLECON: A spatially explicit model for ecological economics of species conservation in complex forest landscapes. University of Georgia, United States, Georgia.

• Lucas KE. M.S. (1994). Modelling avian responses to red-cockaded woodpecker habitat management in loblolly pine forests of east-central Mississippi. Mississippi State University, United States, Mississippi.

• Tucker JW, Jr. Ph.D. (2002). Influence of season and frequency of fire on Bachman's and Henslow's sparrows in longleaf pine forests of the Gulf Coastal Plain. Auburn University, United States, Alabama.

Articles

• Allen JC, Krieger SM, Walters JR & Collazo JA. (2006). Associations of breeding birds with fire-influenced and riparian-upland gradients in a longleaf pine ecosystem. Auk. vol 123, no 4. pp. 1110–1128.

• Brauning DW, Brittingham MC, Gross DA, Leberman RC, Master TL & Mulvihill RS. (1994). Pennsylvania breeding birds of special concern: A listing rational and status update. Journal of the Pennsylvania Academy of Science. vol 68, no 1. pp. 3–28.

• Clayton L. (1969). Bachmans Sparrow in Lawrence County. Migrant. vol 40, no 4. pp. 86–87.

• Conner LM. (2002). A technique to locate isolated populations using satellite imagery. Wildlife Society Bulletin. vol 30, no 4. pp. 1044–1049.

• Conner RN & Dickson JG. (1997). Relationships between bird communities and forest age, structure, species composition and fragmentation in the West Gulf Coastal Plain. Texas Journal of Science. vol 49, no 3 SUPPL. pp. 123–138.

• Cox JA & Jones SR. (2004). Use of recorded vocalizations in winter surveys of Bachman's Sparrows. Journal of Field Ornithology. vol 75, no 4. pp. 359–363.

• Danielson BJ, Dunning JBJ & Watts BD. (1990). Landscape Patterns of Population Densities in the Bachman's Sparrow Source-Sink Relationships in a Habitat Mosaic. Bulletin of the Ecological Society of America. vol 71, no 2 SUPPL. pp. 132–133.

• Dean TF & Vickery PD. (2003). Bachman's sparrows use burrows and palmetto clumps as escape refugia from predators. Journal of Field Ornithology. vol 74, no 1. pp. 26–30.

• Dorsey GA. (1976). Bachmans Sparrow Songs and Behavior. Oriole. vol 41, no 4. pp. 52–56.

• Dunning JB, Jr., Borgella R, Jr., Clements K & Meffe GK. (1995). Patch isolation, corridor effects, and colonization by a resident sparrow in a managed pine woodland. Conservation Biology. vol 9, no 3. pp. 542–550.

• Dunning JBJ & Watts BD. (1990). Regional Differences in Habitat Occupancy by Bachman's Sparrow. Auk. vol 107, no 3. pp. 463–472.

• Dunning JBJ & Watts BD. (1991). Habitat Occupancy by Bachman's Sparrow in the Francis Marion National Forest South Carolina USA before and after Hurricane Hugo. Auk. vol 108, no 3. pp. 723–725.

• Engstrom RT, Vickery PD, Perkins DW & Shriver WG. (2005). Effects of fire regime on birds in southeastern pine savannas and native prairies. Studies in Avian Biology. vol 30, pp. 147–160.

• Fingerhood ED. (1992). Bachman's sparrow Aimophila aestivalis. Brauning, D. vol W, p. Atlas of breeding birds in Pennsylvania.

• Haggerty TM. (1988). Aspects of the Breeding Biology and Productivity of Bachman's Sparrow in Central Arkansas USA. Wilson Bulletin. vol 100, no 2. pp. 247–255.

• Haggerty TM. (1992). Effects of Nestling Age and Brood Size on Nestling Care in the Bachman's Sparrow Aimophila-Aestivalis. American Midland Naturalist. vol 128, no 1. pp. 115–125.

• Haggerty TM. (1994). Nestling growth and development in Bachman's Sparrows. Journal of Field Ornithology. vol 65, no 2. pp. 224–231.

• Haggerty TM. (1995). Nest-site selection, nest design and nest-entrance orientation in Bachman's Sparrow. Southwestern Naturalist. vol 40, no 1. pp. 62–67.

• Haggerty TM. (1998). Vegetation structure of Bachman's sparrow breeding habitat and its relationship to home range. Journal of Field Ornithology. vol 69, no 1. pp. 45–50.

• Hardin KI, Baskett TS & Evans KE. (1982). Habitat of Bachmans Sparrows Aimophila-Aestivalis Breeding on Missouri USA Glades. Wilson Bulletin. vol 94, no 2. pp. 208–212.

• Hipes DL & Jackson DR. (1996). Rare vertebrate fauna of Camp Blanding Training Site, a potential landscape linkage in northeastern Florida. Florida Scientist. vol 59, no 2. pp. 96–114.

• Krementz DG & Christie JS. (1999). Scrub-successional bird community dynamics in young and mature longleaf pine-wiregrass Savannahs. Journal of Wildlife Management. vol 63, no 3. pp. 803–814.

• Liu J. (1993). Discounting initial population sizes for prediction of extinction probabilities in patchy environments. Ecological Modelling. vol 70, no 1-2. pp. 51–61.

• Liu J, Duning JB, Jr. & Pulliam HR. (1995). Potential effects of a forest management plan on Bachman's sparrows (Aimophila aestivalis): Linking a spatially explicit model with GIS. Conservation Biology. vol 9, no 1. pp. 62–75.

• Liu JG, Cubbage FW & Pulliam HR. (1994). ECOLOGICAL AND ECONOMIC-EFFECTS OF FOREST LANDSCAPE STRUCTURE AND ROTATION LENGTH – SIMULATION STUDIES USING ECOLECON. Ecological Economics. vol 10, no 3. pp. 249–263.

• Murray RL, Stanton TP & Emrick VR. (2004). Bachman's Sparrows mimic the vocalizations of the Common Yellowthroat and the Indigo Bunting. Journal of Field Ornithology. vol 75, no 1. pp. 51–52.

• Perkins DW & Vickery PD. (2005). Effects of altered hydrology on the breeding ecology of the Florida Grasshopper Sparrow and Bachman's Sparrow. Florida Field Naturalist. vol 33, no 2. pp. 29–40.

• Perkins DW, Vickery PD & Shriver WG. (2003). Spatial dynamics of source-sink habitats: Effects on rare grassland birds. Journal of Wildlife Management. vol 67, no 3. pp. 588–599.

• Plentovich S, Tucker JW, Jr., Holler NR & Hill GE. (1998). Enhancing Bachman's sparrow habitat via management of red-cockaded woodpeckers. Journal of Wildlife Management. vol 62, no 1. pp. 347–354.

• Provencher L, Gobris NM, Brennan LA, Gordon DR & Hardesty JL. (2002). Breeding bird response to midstory hardwood reduction in Florida sandhill longleaf pine forests. Journal of Wildlife Management. vol 66, no 3. pp. 641–661.

• Pulliam HR, Dunning JBJ & Liu J. (1992). Population Dynamics in Complex Landscapes a Case Study. Ecological Applications. vol 2, no 2. pp. 165–177.

• Pulliam HR, Liu J, Dunnjing JB, Jr., Stewart DJ & Bishop TD. (1995). Modelling animal populations in chaining landscapes. Ibis. p. 1) S120-S126, 1995.

• Ritchie TL. (1980). 2 Mid Pleistocene Avi Faunas from Coleman Florida USA. Bulletin of the Florida State Museum Biological Sciences. vol 26, no 1. pp. 1–36.

• Rutledge BT & Conner LM. (2002). Potential effects of groundcover restoration on breeding bird communities in longleaf pine stands. Wildlife Society Bulletin. vol 30, no 2. pp. 354–360.

• Shriver WG & Vickery PD. (2001). Response of breeding Florida grasshopper and Bachman's sparrows to winter prescribed burning. Journal of Wildlife Management. vol 65, no 3. pp. 470–475.

• Stober JM & Krementz DG. (2006). Variation in Bachman's Sparrow home-range size at the Savannah River Site, South Carolina. Wilson Journal of Ornithology. vol 118, no 2. pp. 138–144.

• Tucker JW, Jr., Hill GE & Holler NR. (1998). Managing mid-rotation pine plantations to enhance Bachman's sparrow habitat. Wildlife Society Bulletin. vol 26, no 2. pp. 342–348.

• Tucker JW, Jr., Robinson WD & Grand JB. (2004). Influence of fire on Bachman's sparrow, an endemic North American songbird. Journal of Wildlife Management. vol 68, no 4. pp. 1114–1123.

• Tucker JW, Jr., Robinson WD & Grand JB. (2006). Breeding productivity of Bachman's sparrows in fire-managed longleaf pine forests. Wilson Journal of Ornithology. vol 118, no 2. pp. 131–137.

• Willoughby EJ. (1986). An Unusual Sequence of Molts and Plumages in Cassin's Sparrow Aimophila-Cassinii and Bachman's Sparrows Aimophila-Aestivalis. Condor. vol 88, no 4. pp. 461–472.

• Wilson CW, Masters RE & Bukenhofer GA. (1995). Breeding bird response to pine-grassland community restoration for red-cockaded woodpeckers. Journal of Wildlife Management. vol 59, no 1. pp. 56–67.

• Zink RM. (1982). Patterns of Genic and Morphologic Variation among Sparrows in the Genera Zonotrichia Melospiza Junco and Passerella. Auk. vol 99, no 4. pp. 632–649.