WYOMING – Black-footed ferrets are nocturnal, and they spend most of their life below ground in prairie dog burrows. That makes counting them no easy task.
Monitoring populations of these elusive mammals requires overnight surveys on the prairie dog colonies where ferrets have been reintroduced. From sunset to sunrise in late summer, volunteers from the department and our partner agencies use high-powered spotlights to scan the prairie for ferrets’ eyeshine.
Wyoming Game and Fish nongame biologist Dana Nelson explains, “Eyeshine is a phenomenon that occurs when light reflects off of a structure (called the tapetum lucidum) in the back of a nocturnal animal’s eye.
But, Dana, how do we know those eyes looking back at us when we aim a flashlight across a nighttime prairie scene are actually black-footed ferrets and not some other nocturnal critter?
“Fortunately for us, different wildlife species have different colors of eyeshine. The black-footed ferret’s eyeshine is a unique shade of emerald green that reflects back and excites surveyors who get to see this endangered species in the wild,” Nelson says. “After seeing the ferret’s eyeshine, surveyors will attempt to live-trap the ferret so biologists can mark, count and then vaccinate it against plague and canine distemper before being releasing it back to its burrow.”
Game and Fish conducts annual surveys to determine how many ferrets are present and reproducing in reintroduction areas near Shirley Basin and Meeteetse. The information gained from spotlight surveys is essential to determine how each ferret population is contributing to federal and state recovery goals and to determine whether additional management actions are needed to support this endangered species with a special history in Wyoming.
