At this time of year, as soon as the daytime temperatures start to reach into the forties and above, we begin to see snakes coming out of their winter dens. Two common snakes in DuPage County are both garter snakes, from the genus Thamnophis which includes 30 species worldwide.
The Eastern Garter Snake, Thamnophis sirtalis and the Plains Garter Snake, Thamnophis radix spend the winter in underground dens containing several dozen to several hundreds of individuals. Winter is a period of dormancy where these snakes enter brumation, an extreme slowing down of their metabolism.
A garter can be up to 30″ long, black/brown backs, yellow stripes on their sides and a gray-green belly. Usually found in meadows, light forests, marshes and vacant lots, they enjoy a warm spot such as open rocky/paved surfaces warmed by sunlight or hanging out in bushes or logs in the sun. Their meals include insects, earthworms, slugs and fish. Nights are spent under logs, rocks or leaf litter protected from wind and rain.
There are a variety of methods used to study snake species, one of which involves using cover boards. Boards are approximately two square feet, made of plywood, aluminum siding or heavy rubber. These are placed in likely spots where snakes will be found. The snakes use the boards during the day for shelter, rest and warmth. When snakes are found under the boards we identify each snake, weigh and measure it, take lots of pictures and note any markings or injuries. We also record location, weather, time of day and any activity observed. Finding a variety of individuals helps to establish population numbers; finding the same individuals more than once helps to identify whether snakes are moving to different locales during the year.
Discover more from Discover-Nature
Subscribe to get the latest posts sent to your email.
