Original description: Fringilla pusilla Wilson 1810
Taxonomic history in AOU/AOS Check-list
AOU 1 (1886): Field Sparrow, Spizella pusilla
AOU 2 (1895): Field Sparrow, Spizella pusilla; Western Field Sparrow, Spizella pusilla arenacea
AOU 3 (1910): Field Sparrow, Spizella pusilla pusilla; Western Field Sparrow, Spizella pusilla arenacea
AOU 4 (1931): Eastern Field Sparrow, Spizella pusilla pusilla; Western Field Sparrow, Spizella pusilla arenacea
AOU 5 (1957): Field Sparrow, Spizella pusilla pusilla, Spizella pusilla arenacea
AOU 6 (1983): Field Sparrow, Spizella pusilla
AOU 7 (1998): Field Sparrow, Spizella pusilla
In the pre-Linnaean days of Mark Catesby, “Little Sparrow,” or “Petit Moineau,” was as good a name as any. Jacob Theodor Klein latinized that label as “Passerculus simpliciter,” “just a small sparrow,” and coined for it the expressive German name “Brauner Zwerg,” the brown dwarf.
Working from Catesby’s brief description and the accompanying plate he praised, rather indulgently, as “an exact figure,” the French ornithologist Mathurin Brisson offered a slightly more informative name based on the species’ known range in the American southeast, “Passer virginianus,” the Virginia Sparrow. Catesby’s description of the bird as “usually seen single, hopping under Bushes,” led Thomas Pennant to assign the species a habitat name; uncertain about its broader taxonomic affinities, he called it the Bush Warbler.
Pennant’s name was hardly more eloquent than any that had come before, but in a strange and accidental way, it would influence the Field Sparrow’s nomenclatural history for the next fifty years. Pennant’s junior colleague John Latham relied on the older man’s Arctic Zoology in listing the species in his General Synopsis. Unfortunately, Latham misread the English epithet “bush” as “rush,” transforming the bird of low shrubs into a palustrine species; his spurious Rush Warbler then served as the basis for the sparrow’s entry into the Linnaean tradition, when Johann Friedrich Gmelin included Motacilla juncorum (“rush warbler”) in his edition of the Systema naturae. As late as 1840, Thomas Nuttall was still using the inappropriate juncorum as the species epithet for the Field Sparrow.
Inappropriate or not, juncorum would have priority over Alexander Wilson’s species name pusilla—if it were agreed that Catesby, Brisson, Pennant, Latham, and Gmelin were in fact naming the same bird that Wilson would later paint. Doubt was first sown by Spencer Baird, who criticized Nuttall for “supposing” that the earlier authors had been describing the Field Sparrow; and even if so, Baird wrote, those descriptions had been unacceptably vague, “scarcely a sufficient diagnosis upon which to found a species.” Baird’s authority was such that the epithet juncorum has not been used since.
There was, however, one other competing species name, introduced, or rather re-introduced, into the scientific record by Elliott Coues. In 1791, William Bartram published “a nomenclature of the birds of passage” he had observed on his travels in the southeastern United States, among them what he called Passer agrestis, “the little field sparrow.” Coues argued both that Bartram’s scientific name was strictly binomial and that the words “little field sparrow,” taken in conjunction with Bartram’s introductory remarks to the list, constituted an adequate description, thus making agrestis a valid scientific name—and one with significant priority over Wilson’s. No one else was convinced, but Coues would use the Bartramian agrestis for this species from 1875 to nearly the end of his life, only grudgingly recognizing the validity of Wilson’s pusilla in the last edition of his Key. Coues’s colleagues at the American Ornithologists’ Union adopted pusilla from the beginning; the final nail was set in 1957, when the International Commission on Zoological Nomenclature ruled all of Bartram’s
“bird names invalid, leaving Wilson as the original describer and naming authority for the Field Sparrow.”
Wilson’s original assignment of the species to the broadly construed finch genus Fringilla, followed by Audubon in his earliest treatment of the Field Sparrow, was briefly rejected in favor of an allocation to Emberiza, another genus of miscellaneous content, before Charles Bonaparte’s Spizella was almost universally accepted for this and the other small, long-tailed brown sparrows. Only Jean Cabanis, who proposed Spinites on linguistic grounds, and George Robert Gray, who folded Spizella into a greatly expanded Zonotrichia, declined to recognize the Bonapartean genus.
Relationships: The Field Sparrow is most closely related to the Brewer, Timberline, and Worthen Sparrows. Those species share the genus Spizella with the Black-chinned, Clay-colored, and Chipping Sparrows; Spizella is in turn most closely related to the Black-throated, Five-striped, and Lark Sparrows and the Lark Bunting.
IUCN Conservation Status: Of least concern
Over most of its range, this remains a common species; its abundance in many of the eastern portions of its distribution is probably greater now than before European settlement, when the early second-growth habitats it requires for nesting were scarce. The recent decrease in some eastern populations is also related to habitat: as old fields undergo natural succession or are replaced by suburban and agricultural development, Field Sparrows are deprived of nest sites. The species is listed in Maine as a Species of Greatest Conservation Need, and in 2016 was scored as of moderate conservation concern in North America.
Behavior: Field Sparrows are often rather shy for a Spizella, keeping their distance from human observers and flying off in strong swooping flight when startled. Disturbed on the brushy fields where they breed and in the thickets and hedgerows where they winter, Field Sparrows drop to the ground or retreat into thick vegetation for minutes at a time, finally emerging to feed in short grass. Feeding birds are quiet, often barely moving as they take seeds and small insects from the ground or low-hanging vegetation. They are also known to survey an area from a low perch before “pouncing” on any insects discovered.
Males deliver their songs from prominent perches in their breeding territory, slender blackish tails depressed and small round heads thrown back.
Voice: The clearest distinction between the Field Sparrow and the Worthen Sparrow is not visual but vocal. Male Field Sparrows sing two songs, the familiar sweet “simple” song and a less frequently heard “complex” song. The simple song, heard as soon as males arrive on the breeding grounds in spring, is a series of clear, bright slurred whistles accelerating into a fast but still musical tremolo; some birds pause briefly in the middle of the tremolo, thus ending their song with two or even three discrete trilled phrases. Most songs remain on or near a single pitch, but in some the tremolo is higher or, less frequently, lower than the introductory whistles; occasionally, the notes in the concluding portion of the song are slowed and rise in a chromatic scale, recalling the similarly rising, but buzzy, song of the Prairie Warbler with which this species shares overgrown fields in much of its range.
The complex song, commonly given when males eject an intruder and “signal[ing] heightened aggressive tendencies,” begins with a tremolo and ends with more widely separated slurred notes. While all the notes of the simple song are typically clear and “pure” in tone and evenly slurred, the notes of the tremolo in this complex song are harsher and more modulated.
Field Sparrows call frequently at all times of the year. The tsee call is short and sharp, with a clear attack and rapid decay; the chip note, perhaps the most frequently heard call, is high and bright, often surprisingly loud for such a small bird and sometimes calling to mind a distant Northern Cardinal or White-throated Sparrow.
Detailed description and measurements drawn from standard reference works
Adult Spizella pusilla pusilla: Tail feathers deep brownish black with narrow pale whitish edges. Upper tail coverts and rump pale brown with very faint darker shaft streaks. Back and scapulars rusty brown, each feather with narrow black shaft streak and narrow pale buffy edges. Primaries and secondaries dark brown with narrow paler edges on outer wing, whitish or buff on primaries and rusty on secondaries. Tertials blackish brown on outer web with broad rusty edges, gray on inner web with inconspicuous buffy edges. Greater coverts blackish with broad buffy edges and extensive whitish tips, forming well-defined wing bar. Median coverts blackish with extensive whitish tips, forming well-defined wing bar. Marginal coverts of under wing pale gray. Nape unstreaked pale brown or tan.
Under tail coverts and vent light grayish buffy, passing smoothly into pale whitish belly; throat whitish, breast whitish with variable bright buffy tinge, usually strengthening into patch at each side of breast. Flanks buffy. Throat dull white with indistinct pale buffy or brown lateral stripe; poorly defined jaw stripe whitish with strong buff tinge, bordered above by inconspicuous rusty whisker.
Crown rusty brown with poorly defined gray median stripe, sometimes absent. Ear coverts gray with buffy or rusty flecking, divided from jaw stripe by inconspicuous rusty whisker. Rusty line behind eye curls on neck side to border ear coverts above and behind. Bright, complete white eye ring. Broad gray supercilium continues to base of bill above lore. Side of head grayer overall in alternate plumage. (26)
Tarsus and toes pink. Short, thick-based bill orange-pink, slightly darker on culmen.
Juvenile Spizella pusilla pusilla: Tail feathers dark brownish with narrow pale edges. Upper tail coverts and rump grayish buff. Back and scapulars dull buffy with narrow black streaks. Primaries and secondaries brown with narrow whitish edges. Tertials brown with rusty edges, brightest part of entire plumage (26). Greater and median coverts dusky with buffy edges and buffy tips, forming well-defined pale wing bars. Marginal coverts of under wing gray. Nape dull grayish brown with narrow black streaks.
Under tail coverts and vent dull whitish with slight buffy tinge, passing smoothly into whitish belly; breast and flanks buffy whitish with dark streaks or spots. Throat unstreaked whitish with poorly defined lateral stripe; poorly defined jaw stripe whitish brown, bordered above by poorly defined dusky whisker.
Crown dull gray with brown cast towards nape; faintly streaked blackish. Ear coverts gray with buffy flecking. Dull off-white eye ring. Broad dull gray supercilium continues to base of bill above lore.
Tarsus and toes dull yellowish pink. Short, thick-based bill gray at base, pale yellowish or pinkish at tip.
Length 119-139 mm (4.5-5.5 inches)
Wing 59-67 mm (2.3-2.6 inches)
Tail 54-65 mm (2.1-2.5 inches)
Mass 12-14 g