Abstract

The Rio Grande cooter (Pseudemys gorzugi) is a conservation-reliant riverine turtle native to the lower Rio Grande basin and its tributaries. Although research on this species is expanding, significant gaps remain in our understanding of its nesting ecology. To fill in some of these gaps, we conducted surveys from 2020 to 2022 of the Rio Grande cooter on the Black River in New Mexico, aiming to document the habitat, incubation period, predation, and seasonality of nests. We used satellite telemetry and visual encounter surveys to locate nests and characterize the habitat along with deploying protective nest cages and game cameras to identify predators and determine incubation periods. We found nests at a mean distance of 5 m (± 4.2 SD) from the water’s edge. Locations tended to be clustered, with 95% of nests being within 0.5–75 m of at least 1 other nest. Out of 5 intact nests, 2 nests successfully hatched in September after incubation periods of 78 and 91 d. Raccoons (Procyon lotor) were the only predators observed at nests monitored with game cameras. All 5 direct observations of nesting occurred in mid-June, whereas additional ultrasound images of 155 P. gorzugi, collected May–July, revealed a peak in the proportion of gravid females from late May to June. Overall, our findings provide baseline data on nesting events and nest locations of P. gorzugi along the Black River. This knowledge will aid in the planning of future nesting ecology studies on the Black River and provide a framework for conservation measures, including identifying possible locations for protective buffer zones where human and predator disturbances are reduced during peak nesting and hatchling emergence periods.