Searching for Snakes in Southwest Michigan
Each spring the eastern massasauga rattlesnake emerges from crayfish burrows and other winter hibernation holes ready for some sun and a good meal to kick-start its growth and reproduction for the year. This emergence coincides with a new spring tradition for the Eastern Massasauga Rattlesnake Species Survival Plan® (SSP), which manages the snake’s population in zoos across the country.
In early May we gather at a site in southwest Michigan to conduct field surveys for the snake in hopes of better understanding its population dynamics—the mortality, reproductive and population-growth rates of the snake population. To do that, we need to find the snakes (the hardest part!), capture them, mark them with a microchip (the same kind you put in your pets) and set them loose again so we can hopefully recapture them in future years.
Eastern massasauga rattlesnakes are endangered or threatened throughout most of their range in the central and northwest United States and southern Canada. The species is currently a candidate for full federal protection under the Endangered Species Act.
Beyond coordinating this study in Michigan, Lincoln Park Zoo is heavily involved in the SSP and has conducted survey work in the Chicago region for the snake. The Michigan field work brings together snake experts—both in zoo management and surveying for wild populations—from 14 zoos across the United States, three federal and state wildlife agencies, two universities and the private foundation in Michigan where we conduct the surveys.
During our week in the field, we spend 5–7 hours per day surveying, which one participant describes as “randomly wandering around with your head down” and carefully looking for a snake in very similar looking vegetation. Ah, camouflage.
We also spend a lot of time worrying about the weather—snakes typically won’t be active in cool temperatures or heavy rains (luckily for us, these are also field biologists’ least-favorite field conditions). With a limited time for surveying, we don’t want to miss a day because of poor conditions.
Our ultimate goal for the week is to find even more snakes then we captured last year (20 snakes) and re-capture some of our individuals from last year, if possible. We’ll see what the week—and the weather—brings.
Lisa Faust, Ph.D., is a research biologist in the zoo’s Alexander Center for Applied Population Biology.