Abstract

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Schlicht, D. and M. Saunders. 1995. Completion of status surveys for the dakota skipper (Hesperia dacotae) and the poweshiek skipper (Oarisma poweshiek) in Minnesota. Final report submitted to the Nongame Wildlife Program, Minnesota Department of Natural Resources. Unpaged.

Abstract:

During late June and July of 1993 and 1994, a survey of 60 prairie areas in Minnesota was conducted for three prairie obligate butterfly species. These species were: Hesperia dacotae (Skinner), the Dakota Skipper; Oarisma poweshiek (Parker), the Poweshiek Skipperling; and Speyeria idalia (Drury), the Regal Fritillary. The Dakota Skipper is a candidate for listing under the Endangered Species Act by the U.S. Fish and Wildlife Service and is listed as Threatened in Minnesota.

To insure that fieldwork would begin at the time of the emergence of H. dacotae, records were consulted to determine that date, and reconnaissance surveys were made beginning June 24 (175), 1993 and June 28 (179), 1994 on known population sites until it emerged. Both H. dacotae and O. poweshiek were found on July 5 (186), 1993 and S. idalia was first seen on July 8 (189), 1993. In 1994 all three species were found on June 29 (180). Weather and flooding permitting, surveying continued through July 18, 1993 (199) and July 12 (193), 1994. Fifty four of the 60 listed prairies were visited in 1993, but because several prairies had multiple parts and weather created less than ideal conditions, 69 visits were accomplished. During the 1994 season 41 prairies were sampled, most were revisits from 1993.

The sites were prioritized by previous records for these butterflies and by prairie quality. H. dacotae was found in 4 of 19 sites on which it had previously been recorded and in 3 new sites for a total of 7 of 63 prairies. In 1994 it was found on 3 sites, one of which was new. O. poweshiek was found in 11 of 19 sites on which it had been recorded and in 13 new sites for a total of 25 of 63 prairies. S. idalia was found in 15 of the 63 prairies.

Due to unusual weather and extensive flooding, both butterfly and human activities were not normal in 1993. Populations, when found, were very small and often very restricted on the site. In 1994 the weather was more normal and the season early in the north but the same trends were evident. During 1994 H. dacotae was not found on 2 of the 1993 sites.

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