Original description: Fringilla aestivalis Lichtenstein 1823
Taxonomic history in AOU/AOS Check-list
AOU 1 (1886): Pine-woods Sparrow, Peucaea aestivalis; Bachman’s Sparrow, Peucaea aestivalis bachmanii
AOU 2 (1895): Pine-woods Sparrow, Peucaea aestivalis; Bachman’s Sparrow, Peucaea aestivalis bachmanii
AOU 3 (1910):Pine-woods Sparrow, Peucaea aestivalis aestivalis; Bachman’s Sparrow, Peucaea aestivalis bachmani
AOU 4 (1931):Bachman’s Sparrow, Aimophila aestivalis bachmani; Pine-woods Sparrow, Aimophila aestivalis aestivalis
AOU 5 (1957): Bachman’s Sparrow, Aimophila aestivalis bachmani, Aimophila aestivalis aestivalis
AOU 6 (1983): Bachman’s Sparrow, Aimophila aestivalis
AOU 7 (1998): Bachman’s Sparrow, Aimophila aestivalis
IUCN Conservation Status: Near-threatened
Habitat: The old alternative name Pinewoods Sparrow obscures the fact that this species breeds in two quite different habitats in different portions of its range. In the south and east, Bachman Sparrows are found almost exclusively in open pine forests with a grassy understory punctuated by shrubs and short trees. In the north and west, however, the preferred habitat is—or in most such areas, was—abandoned pastureland,
“usually fallow for four years or more, which is well grown up with goldenrods and asters, various grasses, and the miscellaneous composites and weeds typical of dry, eroded slopes. The presence or absence of pine seedlings seems to have no bearing…. This species is practically confined to hill country, almost never appearing in the valleys or even on the lower slopes of the hills. A typical territory is near the top of a slope where eroded gullies have been healed and are covered with shrubs, particularly blackberry bushes.”
Behavior: This is an extremely furtive sparrow, reliably seen only when males sing from an open perch on a pine branch. Birds feed almost exclusively on the ground, walking and hopping slowly, usually silent, beneath grassy cover. If disturbed, they fly straight away from the observer and disappear some distance away on the ground beneath a dense palmetto or other shrub; on landing, they may scurry into holes or burrows constructed by small mammals or reptiles, a behavior also recorded in Cassin and Black-throated Sparrows.
Happily for the human observer, male Bachman Sparrows often take conspicuous perches to sing atop bushes or from horizontal limbs in the open canopy of a tall pine. Bachman Sparrows do not commonly sing in flight, though males may continue to sing on take-off or begin just before landing.
Voice: Male Bachman Sparrows have a repertoire of three songs: the primary song, a whisper song, and an “excited” song. The variability of the primary song in this species is both geographic and individual. One Florida bird was noted as singing 39 different primary songs, while almost 250 distinct song types were recorded in Florida and Ohio. The most frequently heard is a simple, pleasing phrase comprising a sweet whistled note and a light, loose tremolo; John Bachman described it as deceptively similar to the song of an Eastern Towhee. The whistled note is sometimes slurred up or down, and the tremolo can be higher or lower in pitch than the introduction; the effect is often rather Field-Sparrow-like, though the tremolo is usually noticeably slower, with more space between the notes. Some songs reverse the sequence of these two elements, while others add a second tremolo or insert one or more additional slurred whistles at beginning or end.
The whisper song resembles the primary song in pattern and variability, but is “barely audible to observers at any distance from [the singing] birds.”Once thought to be largely restricted to the earliest stages of nesting, it can apparently in fact be given at any time during the nesting cycle, and is sometimes interspersed in bouts of primary singing.
The “excited” song, given by a perched bird or, occasionally, in flight, is a jumbled set of slurred whistles and tremolos, a continuous whirling series of primary songs uttered fast and without a pause, usually ending with a more typically enunciated primary song. This song can recall the warbled song of a Grasshopper Sparrow or even the song of a Botteri Sparrow.
The adult’s calls include a sharp tink and a high, thin sit with rapid attack and decay. There is also “a series of chip calls run together with sufficiently short intervals between them that the result sounds like a trill of the Chipping Sparrow,” though somewhat slower and less evenly pitched. That “chittering” trill functions both as a reunion duet between the members of a mated pair and as an aggressive call.
Detailed description and measurements drawn from standard reference works
Adult Peucaea aestivalis illinoensis: Tail feathers gray-brown with ashy gray edges; central tail feathers faintly barred. Upper tail coverts and rump rusty brown with faint or absent blackish shaft streaks. Back and scapulars sandy to rusty, with darker centers and broad gray feather edgings forming long streaks. Primaries light rusty brown with grayish edges, secondaries brown with broad rusty edges. Tertials dark gray with narrow pale rusty gray edges and tips. Greater and median coverts reddish with broad blackish shaft streaks and faint paler buffy tips; no strongly contrasting wing bar. Marginal coverts of under wing bright light yellow. Nape rusty with broad gray feather edgings forming short parallel streaks.
Under tail coverts and vent yellowish buff. Belly dull white at center, broadly bordered by deep dull buff of unstreaked or very faintly streaked flanks and breast. Breast and throat deep dull buff, fading on upper throat to grayish buff. Very faint dark lateral throat stripe separates throat from grayish buff jaw stripe. Ear coverts grayish buff.
Crown rusty with broad gray central stripe. Rusty line above ear coverts extends back from fine neat whitish eye ring. Broad buffy gray supercilium continues to base of bill and onto lore.
Tarsus and toes pale brown. Rather long, faintly downcurved bill pale yellow-gray below and on edges of upper mandible, rest of upper mandible dark gray.
Juvenile Peucaea aestivalis illinoensis: Tail feathers gray-brown with ashy gray edges; central tail feathers faintly barred. Upper tail coverts and rump brown with faint blackish shaft streaks. Back and scapulars brownish to rusty, with darker centers and brownish feather edgings forming long brown streaks. Primaries light brown with grayish edges, secondaries brown with broad rusty edges. Tertials dark gray with narrow pale rusty gray edges and tips. Greater and median coverts brownish to dull reddish with broad blackish shaft streaks and buffy edges and tips creating somewhat contrasting wing bars. Marginal coverts of under wing bright light yellow. Nape reddish brown with heavy darker brown streaking.
Under tail coverts and vent buffy. Belly whitish at center, broadly bordered by dull buff of dark-streaked flanks and breast. Breast and throat dull buff with heavy dark brown streaks. Very faint dark lateral throat stripe separates throat from brownish buff jaw stripe. Ear coverts brownish buff.
Crown brown with heavy darker brown streaking. Brown line above ear coverts extends back from very inconspicuous neat whitish eye ring. Broad buffy supercilium continues to base of bill and onto lore.
Tarsus and toes pale brown. Rather long, faintly downcurved bill pale yellow-gray below and on edges of upper mandible, rest of upper mandible dark gray.
Length 124-152 mm(4.9-6.0 inches)
Wing 58-61 mm (2.3-2.4 inches)
Tail 59-62 mm (2.3-2.4 inches)
W:T 1.0
Mass 18-21 g
