Animalia Life

Ammodramus nelsoni
TAXONOMY
Ammodramus caudacutus var. nelsoni Allen, 1875, Cook Co., Illinois. Three subspecies.
OTHER COMMON NAMES
English: Nelson’s sparrow, Acadian sparrow, sharp-tailed sparrow; French: Bruant des Nelson; German: Nelsonammer; Spanish: Gorriуn Coliagudo.
PHYSICAL CHARACTERISTICS
4.5–5 in (11–13 cm); 0.14–0.74 oz (14–21 g). Small, sharptailed sparrows with broad median crown stripe outlined by brown lateral crown stripe, a yellow-ochre stripe above the eye, a brown stripe through the eye, and gray ear coverts and nape. The back is dark brown, usually with distinct grayish or white stripes. Underparts are pale yellow with faint brown streaks on side of throat and flanks. Birds breeding in the maritimes of Canada and coastal Maine are less brightly colored. Sexes are alike. Juveniles lack the grayish color.
DISTRIBUTION
A. n. nelsoni breeds from north Alberta, central Saskatchewan, and south Manitoba to northeast South Dakota and winters along the Gulf Coast and southern coast of California. A. n. alterus breeds on the south coast of Hudson Bay and James Bay and winters along the coast of the United States from New York to southern Texas. A. n. subvirgatus breeds along the coast of the Gulf of St. Lawrence, the coast of Quebec, Nova Scotia, and New Brunswick to central Maine and winters from coastal Massachusetts to northern Florida.
HABITAT
In the prairies, breed in freshwater marshes where cordgrass and whitetop are common. Along the shores of James and Hudson Bays, they are found in dense sedge bogs, generally where there are a few dwarf birch trees. In the maritime provinces and Quebec they are found in rank, wet grassland and salt marshes. During migration, they may be found in wet fields and marshes, often in cattail. In winter they are found along the coast in freshwater and salt marsh habitats, but most commonly in brackish marshes.
BEHAVIOR
Males sing persistently during breeding season and commonly sing at night. They may sing from a bush, from the ground, or during an elaborate aerial display. On the ground, they commonly run.
FEEDING ECOLOGY AND DIET
During breeding season they principally feed on insects and other arthropods but also on small mollusks. In fall and winter seeds become important. They feed while walking through dense grasses or while clambering in vegetation.
REPRODUCTIVE BIOLOGY
Nonterritorial and promiscuous. Only the female provides parental care. The nest is usually a simple cup of coarse grass placed on the ground or just above water in marshes. Nesting takes place in June and July. Incubation of four to five eggs lasts about 12 days, and the young fledge after about 10 days.
CONSERVATION STATUS
Not threatened, though marsh degradation and loss have caused serious problems in some populations.
SIGNIFICANCE TO HUMANS
None known.

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