Eastern persius duskywing: COSEWIC assessment and status report: chapter 6

Distribution

Global Range

The nominate Eastern Persius Duskywing is generally distributed in the Great Lakes region eastward to New England, New Jersey and the Appalachian Mountains (Burns 1964). Specifically, the taxon is known from states in the United States shown in Figure 5 (based on Burns 1964 and NatureServe Explorer 2001). It is believed to have been extirpated from Maine, and has not been reported in Maryland, New Jersey or New York in the last twenty years (NatureServe Explorer 2001); fewer than 20 extant populations are known continent-wide (NatureServe Explorer 2001).


Canadian Range

In Canada, records of nominate Eastern Persius Duskywing supported by valid specimens are restricted to two sites in southwestern Ontario: St. Williams, Norfolk County, and near The Pinery Provincial Park, Lambton County (Figure 6, Appendix 1). Although this species is known from only a few, relatively recent records in Canada, It almost certainly occurred from pre-settlement times as scattered populations in southern Ontario. If it were a vagrant, it would be unlikely to have occurred consistently at the St Williams site over several years, and would be more likely to have turned up at lupine patches much closer to the United States border. In addition, major published works, such as The Butterflies of Canada (Layberry et al. 1998) as well as NatureServe (2001) include the butterfly as an accepted Canadian species. 

Although the first Canadian record of the Eastern Persius Duskywing is from St. Williams in 1972, an earlier record has now been confirmed.  An unidentified and thus unreported specimen that was collected in the Pinery area in 1969 and resides in the private collection of Sid Daniels was examined by Matt Holder and was identified as E. p.  persius. Although one should be cautious with historical records to ensure specimens have not been mislabelled, the Pinery area hosts suitable habitat and is a well-known historical locality for the ecologically related Karner Blue (Lycaeides melissa samuelis Nabokov). Matt Holder thinks it likely that the Eastern Persius Duskywing occurred in the Pinery area and believes the specimen to be correctly labelled.


Figure 5: North American Range of Erynnis persius persius

Figure 5.  North American range of Erynnis persius persius, based on NatureServe Explorer (2001), Opler et al. (1995) and Burns (1964).

Based on NatureServe Explorer (2001), Opler et al. (1995) and Burns (1964).


Figure 6: Canadian Range of Erynnis persius persius

Figure 6. Canadian range of Erynnis persius persius, based on confirmed specimens.

Based on confirmed specimens.

Reports of the Eastern Persius Duskywing from elsewhere in southern Ontario, including Muskoka District Municipality, Manitoulin Island, other sites in Lambton County and Norfolk Township, Middlesex County, Essex County, Niagara Regional Municipality, Hamilton, Toronto and Ottawa (Hess and Hanks 1981, Hess and Hanks 1986, Kulon et al. 1987, Hess 1988, Holmes et al. 1991, Riotte 1992), are not supported by specimens known to M. Holder, or are based on misidentified specimens that M. Holder has examined (Appendix 1). On May 28, 2005, eight adult duskywings purported to be E. p. persius were observed by Brenda Kulon flying over wild lupines at Port Franks Forested Dunes Nature Reserve in Lambton County, but their identification was not confirmed. Moreover, because no voucher specimens were collected and because of the difficulty of identifying E. p. persius with certainty, particularly in the field, there is a high probability that these observations were of E. baptistae or E. lucilius. Matt Holder knows of no other reports or specimens from this site, and Skevington et al. (2001) do not list the species from North Lambton County. Sporadic unconfirmed reports (mostly from non-expert observers) of E. p. persius, especially from southwestern Ontario, are likely to continue. Elsewhere in Ontario, a report from Algonquin Provincial Park in Nipissing District is based on a worn female that the collector believes may be E. lucilius (C. Durden, pers. comm., 2002). Reports of the Eastern Persius Duskywing from Cochrane District, Temiskaming District and further north (and potentially Manitoulin Island) would certainly refer to E. p. borealis, if correctly identified to species; no specimens are known to support these observations (e.g., Hess and Hanks 1979, 1981, 1984, 1985, 1986, 1988) and there are no confirmed records of any subspecies of E. persius from any of these areas. Specimen and observation data are presented in Appendix 1.

Based on existing information, the species was confirmed from two widely separated and isolated sites in southern Ontario. Additional sites where the species may have once occurred include Walpole Island (which had a noteworthy population of wild lupines until its destruction by sandpit operations in 2001 (P.A. Woodliffe, pers. comm., 2002)), a number of sites in the St. Williams area, Toronto, and the Rice Lake Plains east of Peterborough. The historical range of E. p. persius probably included a number of areas within southern Ontario, occupying areas of savannah and prairie that have since been destroyed. Figure 7 presents an estimated distribution of tallgrass prairie and savannah that existed in presettlement times, and shows the patchy distribution of these habitats across southern Ontario. Although it is unknown whether the distribution of E. p. persius mirrored the distribution of these habitats, it does indicate that the distribution of the skipper would have been patchy and disjunct even if it was found in all prairie and savannah habitats. Populations of E. p. persius no longer occur (if they ever did) at Walpole Island (due to the destruction of the site and elimination of host plants) or Toronto, despite recent efforts to restore habitat at the latter locale (City of Toronto 2002). These sites were not visited in 2002 because disturbance and habitat change have very likely eliminated populations of E. p. persius that may have been present. Similarly, a site in Sarnia (Clearwater Nature Trail) was not visited during this study because few lupines are present, and M. Holder considered it unlikely that the area could support a persistent population of E. p. persius given the expected minimum patch size of lupine of about 20 m2 is required to sustain E. p. persius populations (Mo Nielsen, pers. comm., 2005). Fieldwork in Norfolk County, Lambton County and Northumberland County during Spring 2002 (Appendix 2), did not result in any observations or collections of the Eastern Persius Duskywing.

Erynnis p. persiushas not been reported from Pinery in 35 years or St. Williams in 18 years (despite targeted searches in the past and in 2002), and the Eastern Persius Duskywing is probably extirpated from Ontario and Canada.


Figure 7: Pre-settlement Ontario Range of Savannah and Prairie Habitat

Figure 7. Pre-settlement Ontario range of savannah and prairie habitat, based on data from the Natural Heritage Information Centre and the Royal Ontario Museum

Based on data from the Natural Heritage Information Centre and the Royal Ontario Museum.

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