Conservation status and concern
Only one known population remains in Washington, and there is limited information about population status and trends. Efforts are underway to determine the feasibility of translocations to portions of the former range.
Biology and life history
Northern leopard frogs are semi-aquatic, requiring aquatic and terrestrial habitats. They typically overwinter under water, but are primarily terrestrial during summer months. They forage predominately for insects in moist areas. During late spring, males attract females to breeding ponds by vocalizing.
A grapefruit-sized egg mass is deposited just below the water surface and attached to vegetation in warm, shallow, open, still water areas. Eggs may hatch within a few days or weeks depending on conditions. Tadpoles forage mainly on algae and detritus, and complete metamorphosis in 60 to 90 days. Newly metamorphosed frogs emerge from ponds in mid-July through September.
Northern leopard frogs may be preyed on by many species throughout their life history, but the most common are likely mustelids, bullfrogs, and fish.
Description and Range
Distribution and abundance
The last known population of northern leopard frogs in Washington occupies the North Potholes Reservoir Unit of the Columbia Basin Wildlife Area in the Crab Creek drainage. This area has been designated the Northern Leopard Frog Management Area (NLFMA). This species has experienced range-wide declines throughout the western states and Canada.
Historically, northern leopard frogs were found throughout eastern Washington, and 17 occupied sites were recognized throughout the Columbia, Crab Creek, Pend Oreille, Snake, Spokane, and Walla Walla river drainages.
Northern leopard frogs require unique breeding, foraging, and overwintering habitats in close proximity due to their limited dispersal ability. Breeding occurs in shallow, still water areas exposed to sunlight with short, emergent vegetation for egg mass attachment.
In summer, northern leopard frogs forage throughout moist areas, including meadows, fields, irrigation ditches, and scrublands. Northern leopard frogs require deep, well-oxygenated water that does not freeze solid for hibernation. Invasion by non-native vegetation and tall emergent encroachment through wetland succession reduces exposed shoreline, limiting the availability of suitable habitat for breeding and foraging.
Bullfrog colonization and fish entry to the NLFMA by surface water connections during spring flooding increases predation vulnerability. Ideal northern leopard frog habitat would be bullfrog and fish free.