Biology Ph.D candidate Kate Miller treks through a wildflower-lined trail alongside Middletown's Coginchaug River. She approaches a plastic garbage bin and a PCV pipe protruding from the ground. "That's my bat echolocation recorder," she says. “It’s old but I’m not complaining. It was free and it works.” Miller credits Scott Reynolds, Ph.D, of North East Ecological Services in Concord, N.H. for the loan of the equipment. Inside the crude setup is a 12-volt battery, an echolocation call recorder and lap-top computer. Every 1.5 seconds, the equipment translates the information into a graph and stores it as a data file on the…