Schlicht, D. and M. Saunders. 1993. 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.
During late June and July of 1993, 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) on known population sites until it emerged. Both H. dacotae and O. poweshiek were found on July 5 (186) and S. idalia was first seen on July 8 (189). Weather and flooding permitting, surveying continued through July 18, 1993 (199). Fifty four of the 60 listed prairies were visited, but because several prairies had multiple parts and weather created less than ideal conditions, 69 visits were accomplished.
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 2 new sites for a total of 6 of 54 prairies. O. poweshiek was found in 9 of 19 sites on which it had been recorded and in 7 new sites for a total of 16 of 54 prairies. S. idalia was found in 8 of the 54 prairies.
Due to unusual weather and extensive flooding, both butterfly and human activities were not normal. Populations, when found, were very small and often very restricted on the site. Caution should be used in drawing conclusions without doing followup surveys. It is clear, however, that possible trends suggested from the 1993 data are troubling.