Nelson's Sharp-tailed Sparrow

Nelson’s Sharp-tailed Sparrow

Photo Credit: Bill Horn
http://www.birdsofoklahoma.net/index.html

SCIENTIFIC NAME: Ammodramus nelsoni (Allen)

OTHER NAMES: None.

DESCRIPTION: A relatively small (11-13 cm [4-5 in.]) perching bird (Greenlaw and Rising 1994). Distinguishing features include a buffy-orange eyebrow and malar stripe, a grayish ear patch, dark streaking on buffy-orange sides and breast, white belly, gray patch on each side of neck, and a brownish to grayish back with pale streaks (Sibley 1996). Males sing a short gasping song pshhhh’-ipt from conspicuous perches. Flight song and display also sometimes performed. Has recently been split taxonomically from the saltmarsh sharp-tailed sparrow because of differences in morphology, song behavior, and DNA. Three subspecies recognized: A. n. nelsoni, A. n. alterus, and A. n. subvirgatus (Sibley 1996).

DISTRIBUTION: During breeding season, found along east coast from Maritime Provinces of Nova Scotia, Prince Edward Island, New Brunswick, and Quebec south to Massachusetts (A. n. subvirgatus); in wetland areas bordering parts of James Bay and Hudson Bay (A. n. alterus); and in the central Canadian prairies south to northeastern Montana, North Dakota, northeastern South Dakota, northwestern and central Minnesota (A. n. nelsoni). In winter, found along Atlantic Coast primarily from the Carolinas south to northeastern Florida and along Gulf Coast from northwestern Florida peninsula to southern Texas. Also is considered rare in winter in a few areas along the California Coast (Sibley 1996). In Alabama, does not breed, but found in winter in coastal areas with very few inland records (Jackson 2001b).

HABITAT: During breeding season, prefers freshwater marshes, brackish marshes, wet meadows, idle fields, fens, peatlands, and lake margins. Breeding habitats often contain plants like cordgrass, sprangletop, reed, cattail, sloughgrass, sedges, smartweed, and bulrush (Dechant et al. 2001). In migration, may be found in wet fields and marshes. In winter, prefers freshwater, brackish, and saltwater marshes (Rising 1996).

LIFE HISTORY AND ECOLOGY: Arrives on breeding grounds late April to early June. Nests in colonies with home ranges of individuals overlapping. No evidence that a pair bond is formed. Females build nest, incubate eggs, and feed nestlings and fledglings. An open cup nest is built on or just above moist ground in areas usually with dense vegetation and litter from previous years. Clutch size typically three to five eggs, which are laid one per day and are green to bluish white with brownish flecks. Incubation and nestling periods about 11 and 10 days, respectively. Fledgling period about 20 days (Greenlaw and Rising 1994). Departure from breeding grounds begins in late August and most individuals leave by mid-October (Greenlaw and Rising 1994, Sibley 1996). Occurs in Alabama, primarily from September to May (Jackson 2001a). Diet probably similar to closely related saltmarsh sharp-tailed sparrow, and includes insects, mites, spiders, amphipods, snails, and seeds (Greenlaw and Rising 1994).

BASIS FOR STATUS CLASSIFICATION: Partners In Flight (PIF) considers species to be of extremely high priority. In Alabama, designation is due to low relative abundance, very limited winter distribution, a limited breeding distribution, and because future breeding and nonbreeding populations are considered threatened by current and future extrinsic conditions (PIF 2002). Further, secretive habits of this sparrow make population trend data difficult to collect and population declines may be easily overlooked. Alabama coastal marshes are important wintering areas for this species, because it is primarily limited to coastal cordgrass found in brackish and saltwater marshes in winter.

Author: Thomas M. Haggerty