We observed the number of basking female Graptemys geographica (northern map turtles) at 4 basking sites before and after controlled motorboat disturbances using time-lapse cameras. In the 6 hrs following disturbance, the mean number of turtles basking at a site was 43.8% less than before the disturbance; this reduction in use of basking sites suggests that a single boat disturbance event can markedly affect the use of basking sites by female turtles for several hours. The behavioral and physiological impacts of such a shift in habitat use are unclear and should be the focus of future studies.