Box turtle volunteer and researcher Tim O’Brien shares some of his field observations from the past summer.
For the last several years I’ve been tracking some of the sanctuary’s eastern box turtles. The turtles have radio tags attached to their top shells which allow me to locate them with a radio receiver and record their whereabouts.
One of my goals is to get an understanding of the individual ranges of box turtles. Generally speaking, some box turtles are faithful to their territories for undetermined lengths of time. Two of my study turtles have been very predictable in their movements—until one of them wasn’t!
Turtle number 348 is a good example. I’ve tracked this medium-sized male for the past 4 years. This period includes not only weekly monitoring during the active season, but twice monthly checks even when he is brumating (hibernating) in the winter.
Number 348 has exhibited a small home range up in the woods by the Osprey pole. Last summer during a very dry period in August he managed to find his way to Silver Spring and then soaked there for a month. That’s a straight line trip of 1830 feet—more than a third of a mile! Last summer he arrived at Silver Spring on August 5th. How did he even know the pond was there? This year he did it again arriving on August 1st. He only soaked for eight days this time, but he remains in the general area.
It will be interesting to see if he travels back to his regular brumation burrow near the Osprey pole. Box turtles do occasionally change home ranges for various reasons. If he does decide to take up residence on another part of the sanctuary, I’d love to know why. I’ll be keeping an eye on that.
The ultimate unshakeable box turtle may be number 63, a large female who lives in Eastman’s Field.
She brumates up on the ridge behind Goose Pond and travels the entire perimeter of the field between April and November. Her movements are very consistent and in fact I often find her in precisely the same location as the year before at about the same time of year!
Number 63 appears to be smitten with turtle number 238, an older male. I’ve found them mating beneath the same bush at the same time of year two years in a row! This year I found them together in June and although I did not see any mating, it likely did occur.
Unlike other animals, box turtles do not have pheromones or other means of attracting a mate. It’s purely visual cues that bring them together in a chance encounter. In the case of #63 and #238, I find it astonishing that they manage to find each other every year! It is this aspect of their life history traits that makes population density in box turtle populations so critically important.
So what’s next? We are raising a clutch of five box turtles at Bristol County Agricultural High School in Dighton. We plan to release the turtles in June 2020 at the sanctuary. If the turtles continue to grow, they could be about 200 grams each by then (4–5 inches). Our intention is to track them from their release date and gradually increase the size of their radio transmitters as body weight allows. We’ll watch as they establish home ranges and, we hope, continue to grow and thrive. If all goes as planned this will be the first long term box turtle tracking study at the sanctuary with head-started turtles. I can hardly wait to get going!
Special thanks to the amazing students and staff at Bristol County Agricultural High School for their help in head starting our box turtles and terrapins.