Top

Threatened Species: Butler’s Garter Snake

by Beth Fetterly, Urban Ecology Center

One would not normally think that a threatened species would thrive in the most densely populated area of the state. Surprisingly, the Butler’s Garter Snake is found only in Southeastern Wisconsin. Unfortunately its primary natural habitat happens to be in highly-developed Milwaukee County. This snake has a limited range, so it is critical to its survival for us to understand the conditions it needs to survive. Why is it classified as threatened? One of the most obvious answers is habitat destruction. These snakes prefer wetlands and fields, and these spaces are where significant development occurs. The snakes eat worms, frogs, leeches, and salamanders that are found in natural settings. In addition, small pockets of the population have been isolated from each other due to habitat fragmentation. There are only a few confirmed pockets of Butler’s Garter Snakes in the region. This makes it difficult for them to reproduce. To add one more challenge to an already tenuous situation, the Butler’s species may be inadvertently sold as the common garter snake in pet stores because it closely resembles other garter snakes. There are several ways to distinguish between the two species. The Butler’s Garter is smaller as an adult and has a relatively narrower head compared to the neck. It also has a yellow lateral stripe located on the third row of scales, counting up from the large ventral, or belly, scales. Butler’s Garter Snakes do not bite, nor are they poisonous. If you see one, contact the DNR immediately so that the identification can be confirmed and recorded. If you are an avid Riverwest Currents reader, you may remember that an Alverno College student wrote an article last summer about a reptile and amphibian survey she was conducting through the Urban Ecology Center. Because of this survey we now know that Butler’s Garter Snakes live in the park. One of the highlights of this project was finding a pregnant female. These snakes are ovoviviparous, meaning that they produce eggs with a thin membrane that develop within the female’s body. When they hatch, anywhere from four to 17 snakes are born live, and the female is able to reabsorb some of the nutrients from the shells. If you are interested in learning more about native snakes, you can visit the Urban Ecology Center for animal feeding time on Saturdays at 1 p.m. For more information, stop by the Urban Ecology Center in Riverside Park on the west side of the 2800 block of N. Oakland Ave, call (414) 964-8505, or visit www.urbanecologycenter.org. Riverwest Currents – Volume 2 – Issue 7 – July 2003
by Beth Fetterly, Urban Ecology Center