Endangered Resources Program Species Information
Butler's Gartersnake (Thamnophis butleri)

Butler's Gartersnake Photo by A.B. Sheldon. Check the photos tab for additional photos.
Photo © A.B. Sheldon

Species information from the Bureau of Endangered Resources. See also:

Overview

Species Overview

Butler's gartersnakes (Thamnophis butleri), a Threatened Species in Wisconsin, prefer almost any open-canopy wetland type (not open water) and adjacent open to semi-open canopy upland, including prairies, old fields and weedy vacant lots. They also prefer low-canopy vegetation (<24"), although they will occupy habitats with taller vegetation such as reed canary grass. Butler's gartersnakes can be active from mid-March through early November, usually emerging shortly after frost-out and remaining active until daytime temperatures fall consistently below 50 deg. F. Breeding usually occurs in April and early May but can occur in fall and live young are born between mid-July and mid-August.

Status and NHI Documented Occurrences in Wisconsin

The table below provides information about the protected status (State and Federal Status) and the rank (S and G Ranks) for Butler's Gartersnake (Thamnophis butleri). See the Working List Key for more information about the abbreviations used. Counties shaded blue have documented occurrences for this species in the Wisconsin Natural Heritage Inventory database. For invertebrates, dots depict locations from the "Invertebrate Atlas," a database with occurrences of rare and common aquatic and select terrestrial invertebrate species found in Wisconsin and adjacent areas. While the invertebrate atlas is a quality assured database, not all records have been verified. The map is provided as a general reference of where this species has been found to date and is not meant as a range map.

Summary Information
State Status:	THR
Federal Status in Wisconsin:	none
State Rank:	S3
Global Rank:	G4
Tracked by NHI:	Y
Species of Greatest Conservation Need:	Y

Documented locations of Thamnophis butleri in the Natural Heritage Inventory Database as of April 2009.

Book Excerpt

Snakes of Wisconsin Excerpt

This following material was taken from Snakes of Wisconsin, a full color guide. Order a copy of the book here.

Butler's Gartersnake Range map

Size: 15-20 in.

Description: The Butler’s garter snake can be easily confused with the eastern plains garter snake where their ranges overlap in the seven southeastern counties of Wisconsin. The Butler’s tends to be smaller than the eastern plains as an adult. The lateral stripes on the Butler’s garter snake usually occur on scale row three and adjacent halves on rows two and four. The stripes are light yellow to a rich orange-yellow color. Background color is brown, black or olive and there may be a double row of black spots between stripes. This garter snake has an especially small head and a thick neck. The expert opinion of a garter snake specialist is needed to positively identify this species because of the many variable characteristics of this species. Butler’s garter snakes live in wet to dry prairies, marshes, old fields, roadside grassy areas and vacant lots. Earthworms form the bulk of their diet.

Photos

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