Original description: Emberiza Le Conteii Audubon 1843
AOU 1 (1886): Leconte’s Sparrow, Ammodramus leconteii
AOU 2 (1895): Leconte’s Sparrow, Ammodramus leconteii
AOU 3 (1910): Leconte’s Sparrow, Passerherbulus lecontei
AOU 4 (1931): Leconte’s Sparrow, Passerherbulus caudacutus
AOU 5 (1957): Le Conte’s Sparrow, Passerherbulus caudacutus
AOU 6 (1983): Le Conte’s Sparrow, Ammodramus leconteii
AOU 7 (1998): Le Conte’s Sparrow, Ammodramus leconteii
IUCN Conservation Status: Of least concern
Both Christmas Bird Counts and Breeding Bird Surveys suggest modest increases in this species’ population in the United States in the late twentieth and early twenty-first centuries. Its reliance on marshy grasslands as breeding habitat makes it susceptible to habitat loss caused by overgrazing, crop farming, and oil and gas extraction. At the same time, grassland not regularly disturbed by fire or haying is invaded by trees and bushes, rendering it unusable by nesting birds.
Habitat: At all seasons, LeConte Sparrows are found in damp weedy fields, marshy edges, and prairies with little or no woody vegetation.
Behavior: Beginning in the days of Maximilian and Audubon, the LeConte Sparrow has been considered one of the most secretive of sparrows, traditionally compared to a mouse in its fast, erratic movements on the ground. Many migrants and wintering birds are surely overlooked as they walk and hop through the deep litter beneath tall grass, flushing only when disturbed at close range—or even not then: foraging birds can sometimes be very closely approached by the human observer, and will often continue to feed, apparently oblivious, right at their watcher’s feet.
Flushed birds flop and flutter in weak but direct flight away from the source of disturbance, with none of the easy darting and swooping of the Savannah Sparrow. They almost always land in dense cover, but migrants often then slowly climb a grass stem or dried forb to look back at the source of disturbance, offering patient birders their best opportunity for a good look.
Like most grassland sparrows, males are rarely or never heard singing in migration or winter. On the breeding grounds, LeConte Sparrows sing from the ground or from low, often hidden perches in the tall grass; only occasionally do they take the very top of a rush or stalk as a singing perch, making it even more difficult for humans to be certain in every case whether it is a bird or an insect buzzing and ticking from the wet grassland.
Voice: Migrant LeConte Sparrows tend to be relatively quiet, though when alarmed or alert they may give a series of surprisingly low-pitched, smacking notes recalling the chip of a Palm Warbler or even at times a Common Yellowthroat. They also call with a very high-pitched, short, thin tsit, which agitated birds may repeat in a long, fairly fast series; the single vocalization is easily mistaken for an insect sound coming from an autumn field.
The song of territorial males is soft and also insect-like. It begins with a hurried series of two to four very short, slightly buzzy notes and ends with a harsh, low-pitched buzz: tiktetik BRZZ. At any distance, the brief introductory phrase may be inaudible, leaving only the long, irregularly modulated buzz. From a distance, that concluding note can resemble part of the song of a Clay-colored Sparrow, but it is longer, lower-pitched, and “thicker” than the finer, briefer, repeated buzz of that species. The end of the LeConte Sparrow’s song is also not unlike the complete song of the Nelson Sparrow; the buzz of that species is even longer, more coarsely modulated, and slightly slower, usually with a distinctive lower note at the end.
LeConte Sparrows also have an infrequently witnessed longer song, usually given in flight but sometimes delivered from the ground. This song typically is preceded by several of the short, high-pitched call notes, which are followed by a fast rising and falling whistled phrase as the bird flies up; the typical terminal buzz is given just before landing. The “aerial trill” attributed to the LeConte Sparrow in some older sources is likely not produced by this species.
Detailed description and measurements drawn from standard reference works
Adult: Short, pointed tail feathers pale dull brown with very thin darker shaft streaks, the outermost feathers up to half an inch shorter than the inner pair. Upper tail coverts, rump, and lower back pale sandy buff with very fine black shaft streaks. Back feathers and scapulars with blackish centers and broad buffy edges aligning to produce regular dull straw-colored parallel stripes. Primaries dull pale gray-brown, secondaries browner, both with very narrow white edges in fresh plumage. Tertials blackish with broad buff-white edges. Greater coverts dull pale chestnut with small blackish teardrops and very narrow whitish edges; no obvious wingbar. Median coverts black-centered with medium-broad dull pale chestnut edges; no obvious wingbar. Nape feathers chestnut-pink with very broad silvery edges. Belly and lower breast white. Undertail coverts, vent, flanks, breast sides, and center of breast yellowish-buff, with fine narrow blackish shaft streaks forming broken streaks; shaft streaks shortest, narrowest, and sparsest at center of breast, where they may be chestnut rather than black. Throat white to pale yellow-buff, usually without spots or streaks. No strong lateral throat stripe; throat fades into broad orange jaw stripe, which curls behind silvery gray ear coverts to form broad partial ear surround, interrupted at top rear of ear patch by very short, incomplete blackish eye line. No strong whisker dividing ear coverts from ear surround. Broad buffy orange supercilium widest behind eye, brightest above gray lore. Thin, distinct eye ring white below eye, faintly yellow-tinged above eye. Lateral crown stripes blackish with fine pale scaling or streaking; median crown stripe buffy at the bill, whitish back to nape.
Juvenile: Considerably buffier above and below. Back more blackish, light buff feather edges narrower and less brightly dried-grass-colored than in adult. Nape buffy with slight or no chestnut tinge. Buff of underparts often extends onto belly and lower breast; dark shaft streaks more extensive. Throat, jaw stripe, and broad supercilium dull pale buffy orange; ear coverts dull brown-gray. Crown blackish brown with narrow buffy median stripe.
Length 113-117 mm (4.4-4.6 inches)
Wing chord 51-52 mm (2.0 inches)
Tail 49-50 mm (1.9-2.0 inches)
Mass 12-14 g