A Day in the Field
In her last post, Lisa touched on what it’s like to survey for rattlesnakes, but I thought I’d give you a better idea of what we do for 5–7 hours a day in southwest Michigan. Part of the fun involves occasional brushes with poison sumac, crawling ticks and the randomly changing wetland terrain, which can be solid ground one step and mud up to your waist the next. The real challenge, however, is reviewing your knowledge about preferred massasauga habitat and then trying to narrow your search of hundreds of acres of wetlands to where you think the snakes will be.
Wetlands are a general requirement for massasauga habitat. The snakes seem to prefer the specific grass and shrub vegetation, proximity to open water, abundance of prey and suitable overwintering burrows. Accordingly, you walk many exhausting miles in ankle-to-knee-deep swamp carrying field gear to get an idea where those “massasauga homes” may be.
If you happen to find a snake on your first pass-through then great, you know where to continue looking! If you don’t, then you keep searching, hoping to get lucky and find a snake that is doing a great job of blending into its surroundings. The snakes are difficult to see—they often hide beneath vegetation, rarely rattle (despite their name) and are typically pretty shy animals. Their bodies are shades of brown, and it’s really difficult to pick them out even when you know what you’re looking for!
You develop a mental picture of where the snakes should be depending upon the time of day and weather conditions, but that’s a human interpretation—sometimes it appears that snake location is random. A bit of sheer luck is involved in finding them. To get a better idea of the conditions, check out these two photos we took of different snakes sighted them in the field. I guarantee that both have snakes in them, but I challenge you to find them both!
We’ve been successful at finding snakes each day despite these challenges. When we see the snakes, we collect some environmental and behavioral data so we can better understand the conditions influencing activity. We carefully capture the snakes, place them in safe transport containers and bring them back to an Ecolab where we can take size and weight measurements, collect some basic samples and mark them with microchips that will be readable in the future.
So far this week we’ve recaptured two snakes we had found last year—we use a scanner to read their microchips, each of which has a unique number. After we’re finished with our “processing,” we transport the snakes back out into the field and release them at the same site we captured them.
The surveying is hard work and sometimes monotonous, but the excitement of finding a snake is pretty high—I’m still looking for my snake for this year!
Dan Boehm is the zoological manager of Regenstein Small Mammal-Reptile House and the Pritzker Family Children’s Zoo.