Figure 298. Nelson’s Sharp-tailed Sparrow is a rare winter visitor to California’s coastal estuaries, with transients very seldom encountered in other habitats. The CBRC reviewed records of this secretive sparrow until 1986. This first-winter bird was photographed on 6 February 1977 at one of the species’ regular wintering sites, Bolinas Lagoon in Marin County (1977-014; Bruce Sorrie).

 

 

 

 

 

NELSON’S SHARP-TAILED SPARROW Ammodramus nelsoni Allen, 1875

Accepted: 30 (94%)	Treated in Appendix H: no
Not accepted: 2	CBRC review: records through 1986
Not submitted/reviewed: 19	Large color image: Figure

In light of differences in song, breeding behavior, plumage, and bill shape (Greenlaw 1993) and evidence of limited gene flow (Rising and Avise 1993), the Sharp-tailed Sparrow was split into two species (AOU 1995). The resultant species are the Saltmarsh Sharp-tailed Sparrow (A. caudacutus) and Nelson’s Sharp-tailed Sparrow. Although their identification can be difficult (Parkes 1992, Sibley 1996), no evidence suggests that caudacutus has reached the West. Excepting a specimen from western Pennsylvania (Parkes 1992), a specimen possibly from Michigan (Sibley 2005), and unconfirmed reports from the Gulf coast of Florida and Alabama, caudacutus is unknown more than a short distance from the Atlantic Ocean.

Nelson’s Sharp-tailed Sparrow includes three subspecies that breed in discontinuous ranges and that winter in coastal salt marshes, primarily from Virginia south to Florida and from there west to southern Texas and, rarely, northern Tamaulipas. The species is casual in the interior of North America during winter. Two subspecies are not known for long-distance vagrancy: A. n. subvirgatus, which breeds from the Maritime Provinces south to coastal New Hampshire, and A. n.alter, which breeds around James Bay. Subspecies nelsoni has the widest distribution, breeding from the southern Northwest Territories, northeastern British Columbia (rare), and extreme northeastern Montana east to northern Manitoba and south locally to northwestern Wisconsin. Some of these birds winter in California’s coastal salt marshes. Migrants are very rarely recorded anywhere in the West. Extralimital records come from Wyoming, Colorado, western Texas, central New Mexico (NAB 58:119), southeastern Arizona (NAB 58:124), northeastern Washington, and southwestern British Columbia. A bird collected on 2 February 1961 at Bahía de San Quintín in Baja California (Northern 1962; LACM 38067) suggests that small numbers may winter south of California, at least sporadically.

California’s first Nelson’s Sharp-tailed Sparrow was collected on 6 May 1891 at Milpitas, Santa Clara County (Ridgway 1891). Very few were recorded in the state through the 1960s, but by the time CBRC review ended in 1986 this retiring sparrow had come to be known as a rare and very local winter visitor to California’s large coastal marshes, as well as a very rare coastal fall migrant. Favored sites include Humboldt Bay (Humboldt County), Bolinas Lagoon (Marin County), south San Francisco Bay (Santa Clara and Alameda Counties), Morro Bay (San Luis Obispo County), Anaheim Bay and Upper Newport Bay (Orange County), and the greater San Diego Bay area (San Diego County). Birds occasionally winter in other weedy habitats near the coast, for example, near Port Hueneme, Ventura County, in February 1999 (NAB 53:210) and January/February 2002 (NAB 56:225). The state’s only island records refer to two October vagrants from Southeast Farallon (Richardson et al. 2003). The earliest fall date for this species is 22 September (see the following paragraph). Winter records tend to occur between mid October and late January, and the species is very seldom recorded past the end of March, although the latest date for a likely wintering bird is 6 May (referring to the state’s first record, discussed previously).

Only a handful of Nelson’s Sharp-tailed Sparrows have been found in the state’s interior, four of them spring vagrants: Oasis, Mono County, 25–26 May 1976; Furnace Creek Ranch, Inyo County, 27–29 May 1976; Mojave, Kern County, 13 May 1990 (AB 44:498); and Galileo Hill, Kern County, 20–24 May 1990 (AB 44:498). Three involve fall vagrants, all in late September: Furnace Creek Ranch, 22 September 1990 (Patten and Radamaker 1991) and 27 September 1995 (FN 50:118), and a first-year female at Twentynine Palms, San Bernardino County, 26 September 1995 (FN 50:118, SBCM 54754). A bird that probably wintered locally was recorded on 29 March 1975 at West Pond near Imperial Dam, Imperial County (Garrett and Dunn 1981, Rosenberg et al. 1991; no CBRC review), and a first-year female was collected on 6 December 1996 at Harper Dry Lake, San Bernardino County (SBCM 55295).