Noodles in a Haystack
Eastern massasauga rattlesnake research at SWMLC’s LaGrange Valley Wetlands
Guided by memory and a navigation app on his phone, SWMLC’s Conservation & Stewardship Director Mitch Lettow blazed the trail, breaking through forests of broken cattail stalks, hunching under thickets of poison sumac, and avoiding seemingly innocent mud wallows. Loaded down with gear, it took the researchers 45 minutes to hike to the project area deep within LaGrange Valley Wetlands (LGVW), SWMLC’s recently acquired 427-acre preserve in Cass County. The trek was strenuous – but worth it – to document the property’s now-protected population of federally endangered eastern massasauga rattlesnakes (Sistrurus catenatus) (EMRs).
LaGrange Valley was once a 250-acre human-made lake that has been slowly draining away ever since its dam was removed some 20 years ago. Underwater for over 100 years, the land is slowly readjusting itself as two creeks feel their way through the valley and vegetation finds its footing in the mud – some of it native species, and the rest a hodge podge of non-natives like stinging nettle, poison hemlock, reed canary grass, phragmites, and hybrid cattail. Ecologists call habitats like this “novel ecosystems,” because the combination of plant life has not been seen elsewhere and was not here prior to European colonization. It’s also very different from the habitat across the road at Edward Lowe Foundation’s (ELF) Big Rock Valley, where researchers have been studying EMRs for nearly two decades. And though we might not call it “high quality habitat,” the snakes may feel differently.
People have reported occasional sightings of the small, shy rattlers at LGVW but we wanted more concrete proof. Gathering baseline information now about the snakes’ numbers, sex, age, and health and comparing that to data we collect in the future will help us better understand if our habitat management plans have helped or if this population is declining.
♦ How many snakes are here?
♦ If we remove the non-native plants that currently crowd the wetland, will there be more snakes in three years?
♦ Will we catch the same snakes again, or a crop of young ones that indicate the animals are reproducing well?
♦ Is the population so isolated it has become inbred?
♦ If genetic tests agree, will wildlife corridors or other genetic rescue efforts be needed?
A project like this isn’t just a fun day poking around looking for snakes – it requires a blend of biological science, practical experience, and compassion for the animals being studied – and Adam Austin pulled it all together. Adam is a research associate with The Rattlesnake Conservancy (TRC) and a biological sciences Ph.D. candidate at Western Michigan University. He organized the project, rounded up volunteers (who he trained himself through TRC’s Venomous Snake Handling Courses), and helped secure the permits that allowed the team to legally handle the snakes. “It wouldn’t have happened without Adam,” said Mitch gratefully. Helping guide the project were Dr. Lisa Faust (Lincoln Park Zoo), Dr. Eric T. Hileman (West Virginia University), and Jarod Reibel (Edward Lowe Foundation), along with ten trained volunteers from six states, and documentarian Colleen Kellogg. TRC generously donated the survey equipment SWMLC will need to understand these snake populations.
After the grueling trek through the wetland, the team took a breather then spread out in a line to begin a “meander survey.” Using long poles, they carefully pushed aside plants and debris to look for little rattlesnakes hiding underneath, quietly wishing the humans would go away. Like mushroom hunters, the team kept their heads down and strained their eyes to pick apart the complex crisscross of dried grasses that might disguise the snakes’ pattern of mottled spots melting into shadow. EMRs are so superbly camouflaged that surveyors often walk right past – or over – them!
“Got one!” The team slowly gathered around the lucky surveyor who found a snake and made sure everything was in place for a safe capture: a mobile lab composed of 5-gallon buckets, a tag reader, a scale, and a snake medical kit. A trained volunteer carefully picked up the snake with large rubberized tongs (called “Gentle Giants”) and placed it inside a bucket. There, it could be scanned to see if it had already been tagged and, if not, transferred to a pillowcase (tied off!) for weighing.
The animal was then “tubed”– threaded face-first into a plexiglass cylinder that was (crucially) just big enough to squeeze into, but not so loose that it could just wiggle out the other end. Once the snake was safely stuck inside the tube with its rear-end hanging out, researchers quickly examined it using a sexing probe to determine male or female and lightly squeezing its tummy to see if it was a gravid (pregnant) female (rattlesnakes don’t lay eggs but instead bear live young). Its length and general health were noted, then an identification chip (called a PIT tag) was implanted by lifting a scale and injecting it under the skin in the same way a veterinarian does to a pet.
All this information will be shared with Michigan Natural Features Inventory to add to their statewide database. Finally, a small sample of blood was taken to help researchers understand the genetics of the population.
Over several weeks’ time, researchers conducted surveys at three SWMLC preserves and found 11 snakes of different sizes and sex – a good sign. Sadly, one suffered from advanced snake fungal disease which sometimes spreads between snakes when they overwinter together in moist underground conditions. It will be important to see how many cases of this naturally occurring disease are found in next year’s survey.
Despite that somber finding, we’re thrilled by our expanded ability to study the EMRs that live at our preserves – something that we’ve never been able to do before. Under the guidance of Adam and the team at ELF, Mitch and Stewardship Specialist Dave Brown gained incredibly valuable field experience. And since both recently earned venomous snake handling certification from TRC, SWMLC can now apply for permits that allow us to examine and tag the snakes ourselves.
