Zoo New England presents Horn Pond turtle survey; Blanding's turtle photographed, state to advise on relocation

Kirsten Ward and John Berkeholz of Zoo New England presented survey results to the Woburn Conservation Commission on Dec. 19, 2024, reporting the presence and relative abundance of turtle species at Horn Pond and nearby wetlands. Ward said the team set 16 funnel traps at 20 locations over three weeks, baited with sardines, and checked traps daily to record species, sex and life-stage measurements.

"By far, the most common turtle at Horn Pond from our findings was the painted turtle," Ward told the commission, reporting that "we caught 204 painted turtles" and noting many were likely recaptures because most painted turtles were not individually notched. She described the painted turtles' life history and explained why the team did not notch the common species the way they do rare species.

John Berkeholz described other finds, including snapping turtles (nine juveniles recorded) and nonnative red-eared sliders, which he said appear in small numbers likely deposited from the pet trade. "We found actually 2 adult females and 2 little babies," he said of red-eared sliders, adding that Massachusetts has stopped allowing their sale in-state and that current numbers at Horn Pond do not appear to pose an immediate threat to native species.

The presentation included a photograph of a Blanding's turtle taken by a zoo employee. Berkeholz said the animal appears to be a reproductive female in her 20s–30s with some shell wear and a healed carapace injury. He said the zoo consulted the state herpetologist, Mike Jones, and sent blood tests and other health data to the state. "She's in good health," Berkeholz said, and the presenters are "discussing the proposal or possibility with the state about relocating her to a more healthy population," with Great Meadows in Concord cited as a possible relocation site so she can contribute to the gene pool.

Presenters warned that Horn Pond habitat for Blanding's turtles is marginal and that the species requires larger, better-connected wetlands to sustain breeding populations; Berkeholz said females can travel up to a mile to nest and that road crossings and development threaten connectivity. They also flagged invasive aquatic plants including Asian water chestnut and purple loosestrife in the lagoon and called attention to variable water levels that can affect turtles and fish.

Commissioners asked about methods to distinguish new captures from recaptures; Ward described the notching and measurement protocol used for rare species and explained the team's use of radio transmitters for tracking significant individuals. "We put a radio transmitter on her shell," Berkeholz said, describing an epoxy-mounted transmitter that will transmit for up to three years. He said the tracked Blanding's turtle currently occupies a pool adjacent to the lagoon and that the team will "leave her be" until the state provides guidance in spring.

The presentation concluded with commissioners and community members thanking the presenters and noting strong public interest and volunteer support from Friends of Horn Pond and other local groups. Ward said outreach has generated high engagement and that further targeted surveys, particularly in spring when turtles are more catchable in uplands, could be useful.