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Terrestrial stages of the Red-legged Frog are most typically found at lower elevations, below 200 metres, but have been recorded at over 1000 metres (Ovaska and Sopuch, 2004). It is associated with streams, ponds or marshes, but may also be found far from water in moist forests. It can be found in a variety of stand types of various successional stages, but usually will not remain in clearcuts. Its breeding habitat includes permanent and ephemeral bodies of water with abundant emergent vegetation.

The Red-legged Frog occurs along the Pacific coast of North America from southern British Columbia to Baja California del Norte. In British Columbia, it is found throughout Vancouver Island, the Gulf Islands and the Lower Mainland, west of the Coast Mountains. Its distribution along the coast north of the Fraser River is poorly known, but historical records suggest it may have been found as far north as Kingcome Inlet (Waye, 1999; Ovaska and Sopuck, 2004).

The Red-legged Frog is in the Family Ranidae (true frogs), a large group containing 754 recognized species (AmphibiaWeb 2006), which is found worldwide except for Caribbean and Oceanic islands. In British Columbia, the Red-legged Frog is represented by the Northern subspecies, Rana aurora aurora, which also occurs in Washington, Oregon, and the northwestern corner of California. It is a medium sized frog (snout-vent length 30-100 mm). Its name refers to the translucent red coloration of the undersides of the legs and belly.

As with many species, the main threat to this frog in British Columbia is habitat loss. In the Lower Mainland of BC, increasing wetland loss has reduced connectivity between wetlands (i.e., habitat fragmentation) thus increasing the risk of local extinctions as population losses are not replaced by new immigrants. Isolated populations are then subject to the loss of genetic diversity. Habitat fragmentation resulting from urban development, densification of road networks, and automobile traffic is an ongoing and increasing threat. Road construction can alter wetland habitats, and automobile traffic is an obvious hazard during migration of adults to breeding pools and the dispersal of transformed froglets. Indirect effects may also arise from contaminated water runoff.

The Red-legged Frog is declining in areas throughout its western North American range, including Oregon and California. The introduction of non-native species such as Bullfrogs, Green Frogs, and slider turtles can result in disease transmission, and predation and competition effects at various life stages indicating that complex interactions between habitat alteration, behaviour, and the presence of introduced species may be contributing to population declines.