New York Natural Heritage Program
Mottled Duskywing
Erynnis martialis (Scudder, [1870])

New York State Distribution [-]
Despite the presence of the foodplant, New Jersey Tea (Ceanothus americanus), in the southern part of New York and elsewhere, this skipper is largely absent from all stands of the foodplant east of Ohio. There are records, mostly historical, from Long Island, Albany, Rockland County, Westchester County, and throughout the Hudson Valley, central and western New York, as well as a few scattered sites in the more northern part of the state. It is difficult to know if all of these records were correctly identified, however. More importantly, considering the lack of recent records and the collapse of this species in all neighboring regions, this does not reflect a current range. Glassberg (1993) reports it was already historical with no records in 30 years for the New York City area. It is now historical or extirpated from all four areas covered by that book, and is no longer known extant anywhere in New England, New Jersey, or Pennsylvania. According to Robert Dirig (as of July 2007), the Mottled Duskywing still occurs in the Albany Pine Bush and vicinity, but is much less common than in the past. There also have been credible reports of this species from the Clintonville barrens in 2001 and 2004, and one was photographed on an alvar in Jefferson County in 2004. These three counties in New York comprise the majority or all of the current distribution in the entire Northeast, from Maine to Maryland.

Global Distribution [-]
The historic range is approximately that depicted by Brock and Kaufman (2003). It extended from Massachusetts, Connecticut, and New Hampshire, west across New York and southern Ontario and the Great Lakes states to Minnesota and western Iowa, then south to the Gulf states, and central Texas (Opler and Krizek 1984), west to eastern Nebraska, eastern Kansas, the Ozarks, with disjunct isolated populations in the eastern foothills of the Rocky Mountains in central Colorado, and in the Black Hills (Stanford 1981, Stanford and Opler 1993, Opler 1994, Opler and Krizek 1984). The current range is drastically less than what was once present. The species is now apparently extirpated from New England, New Jersey, at least the eastern half (and possibly all) of Pennsylvania and most of Maryland, and it is very rare in West Virginia and Ohio. However, since 2001 it is still extant in at least three counties in New York. It seems unjustified to consider anything east of Ohio, including Canada, in any range extent estimation since such populations are mostly small, isolated, remnant colonies on a few hundred hectares or less of habitat and, in most cases, destined for extirpation.