GRAYLING, Michigan -- It’s snake week at Camp Grayling. Each spring, dozens of conservation researchers and volunteers descend on the Michigan Army National Guard base in northern Lower Michigan for four days of scientific rattlesnake wrangling. Venomous eastern massasauga rattlesnakes are captured in what’s called a “blitz style” field survey, then are carefully inspected by scientists and returned to the exact spot they were found in nature. Camp Grayling’s resident rattlesnake population is