A standardized drone-based protocol for monitoring freshwater turtles

Basking is an essential thermoregulatory behaviour for freshwater turtles, but accurately estimating basking duration is challenging due to the limitations of traditional survey methods. Traditional methods afford lower detection probabilities, are often disruptive, and they lack precision due to infrequent sampling. To address these limitations, we developed a high-frequency drone-based monitoring method that records repeated, minimally invasive video surveys of individually marked painted turtles (Chrysemys picta). The method involves three main elements:

· Programming an autonomous drone route at fixed, short intervals covering the entire study area

· Recording drone videos to document turtles basking without altering their behaviour

· Manually reviewing video footage to quantify basking occurrence and duration

We implemented this method at a wetland on the Kenauk property in Montebello, Québec, Canada. We monitored 62 painted turtles from June to September 2025. A DJI Mini 4 Pro drone performed an autonomous survey of the wetland every 20 minutes, producing 423 surveys and 127 hours of video over 13 days. Flight initiation distance trials confirmed that surveys conducted at an altitude of 15 m did not initiate escape responses in painted turtles. Drone surveys allow for quantification of individual basking behaviour with unprecedented frequency and without being invasive.