How do we know if a turtle species is at risk? Surveys help establish the health of an existing turtle population in a certain area and let conservationists know what efforts are needed. Population surveys are carried out in many ways — visual sightings, road mortality evaluations and “mark/recapture” studies where turtles are caught, identified with markings and then released again. To evaluate whether headstarting is an effective way to increase population size, the released juveniles are tracked via radio telemetry. A tiny radio transmitter is attached to the juvenile turtles’ shells with epoxy. (The devices don’t hurt the turtles in any way; they are less than 5 percent of the turtles’ body weight.) Each transmitter has a unique frequency that can be detected by beeps on a receiver. Every week, the juveniles are located using this method. A group of wild juvenile turtles is followed at the same time, and the results are compared.
Why do we need to follow these turtles? First, scientists and conservationists need to know whether headstarting programs are working. Do the babies survive? If they do not, we need to understand why. Are the turtles being released in the right place? What size should they be for the best chance of survival? Is there something that can be done differently?
We also need to know whether the released turtles are behaving in the same way as wild juveniles in the area. Are they eating what they should? Are they growing as they should? Are they hibernating successfully (and where are they hibernating)?
Radio transmitters weigh less than a quarter of an ounce (5 g), and are attached painlessly to the turtle’s shell using epoxy.
