Nelson's Sparrow (Ammospiza nelsoni) [XC383489]
by Matt Wistrand from Blue Goose Trail, Sabine National Wildlife Refuge, Cameron Parish, Louisiana, United States (call)
Nelson's Sparrow (Ammospiza nelsoni) [XC860650]
by Andrew Spencer from Reid State Park (near Georgetown), Sagadahoc County, Maine, United States (song)
Subspecies
Ammodramus caudacutus (Sibley and Monroe 1990, 1993) has been split into Sharp-tailed Sparrow (Ammospiza caudacuta) and Nelson's Sparrow (Ammospiza nelsoni) following AOU (1998).
Genus, as currently delimited, is probably polyphyletic. Molecular studies suggest that present species is in a clade with Seaside Sparrow (Ammospiza maritima), Sharp-tailed Sparrow (Ammospiza caudacuta) and Le Conte's Sparrow (Ammospiza leconteii). Has hybridized with Le Conte's Sparrow (Ammospiza leconteii). Until recently considered conspecific with Sharp-tailed Sparrow (Ammospiza caudacuta), but differs in its natural history. The two hybridize in north-eastern USA (southern Maine and northern Massachusetts). Precise ranges of the two on Atlantic coast not fully known, as references to "Sharp-tailed Sparrow" not always clear. Distinctive subspecies subvirgatus perhaps represents a distinct species. Further study is needed. Subspecies alter poorly differentiated from nominate.
The following 3 subspecies are recognised:
nelsoni Allen, 1875 - Breeds in Canada from north-eastern British Columbia and southern Mackenzie Seast through Alberta to central and southern Saskatchewan and central Manitoba, and in northern USA in north, western and south-eastern North Dakota, north-eastern South Dakota and north-western Minnesota. Winters on Pacific coast of south-western USA (California) and in extreme north-western Mexico (northern Baja California) and on Gulf Coast from Texas east to Florida Panhandle, also rarely south to Tamaulipas (north-eastern Mexico).
alter (Todd, 1938) - Breeds in east-central Canada from northern Manitoba east to northern Ontario and western Quebec; probably winters on Gulf Coast of USA (west to Texas).
subvirgatus Dwight, 1887 - Breeds in south-eastern Canada (southern side of St Lawrence R in southern Quebec east to New Brunswick, Prince Edward I and Nova Scotia), and in north-eastern USA south to southern Maine and northern Massachusetts. Non-breeding on Atlantic coast south to South Carolina and northern Florida, casually north to New York.