Abstract

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Keyler, D.E. and K. Fuller. 1999. Survey of timber rattlesnake (Crotalus horridus) peripheral range on southern Minnesota state lands (1998). Final report to the Nongame Wildlife Program, Minnesota Department of Natural Resources, St. Paul, Minnesota. 14 pp.

Abstract:

Field surveys of suitable timber rattlesnake habitat were made on state lands in the counties of Goodhue, Olmsted, and Wabasha from May 9 through September 18, 1998. The primary goal of the study was to determine the status of possible timber rattlesnake populations in this peripheral-range region. Survey areas ranged from the xxxxxx in the north to the northern tip of the xxxxxx in the south, and from xxxxxx, Olmsted County in the west to the xxxxxx in the east.

A total of 143 field man-hours of survey time resulted in the finding of only three specimens of Crotalus horridus. Two specimens, a male and gravid female, were observed on different dates at a single site on state forestland in Olmsted County. This site was historically known as ?xxxxxxx?. The third specimen was evidenced by the sounding of its rattle deep in a talus crevice on a bluff prairie above xxxxxx in the xxxxxx.

Despite the existence of what would be considered good to optimal timber rattlesnake habitat at nearly all survey sites there was no evidence (i.e. shed skins, snake tracks, or broken rattles) to confirm the presence of timber rattlesnakes at any site other than those at which Crotalus horridus were actually observed. Interestingly, landowners adjacent to many of the survey sites in Goodhue and Wabasha counties reported that they had not seen timber rattlesnakes for nearly three decades.

In addition to timber rattlesnakes, 7 other species of snakes, one species of lizard, and 5 species of amphibians were observed during field surveys. However, large numbers of any species were not observed at any site and a total of only 47 herpetological specimens were observed for all sites collectively over the entire season.

In conclusion, based on the results of the current survey, both the range and the numbers of timber rattlesnakes in Goodhue, Olmsted, and Wabasha counties appear to be substantially reduced, or the species extirpated in several areas, which historically supported viable timber rattlesnake populations. These findings strongly demonstrate the need for continued and enhanced habitat protection, population monitoring, and timber rattlesnake protection in Fillmore, Houston, and Winona counties where viable populations still exist.

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Please note that all location information has been removed from this document to protect the timber rattlesnake populations