Winter habitat of northern leopard frogs, Rana pipiens, in a southern Ontario stream

Abstract

The winter habitat of northern leopard frogs (Rana pipiens) in a southern Ontario stream is described from underwater snorkeling observations. Rana pipiens were located beneath rubble (13–40 cm diameter) generally where water depths were greater than 85 cm and the mean mid-depth water velocities were 22.5 cm/s. Water temperatures during the winter ranged between 0.5 and 2.1 °C. Animals were quite torpid but still capable of swimming after being disturbed. Results from a limited marking study suggest that at least some R. pipiens remain in the same stream section throughout the winter months. Competition for similar winter shelters among various species of the stream community is suggested as a possible cause of reduced stream productivity where the availability of such habitats is limited.