Only one native population remains in Washington. Efforts are underway to recover this species in central Grant County. WDFW is partnering with Washington State University, U.S. Fish and Wildlife Service, Oregon Zoo, and Northwest Trek to better understand population status and trends, to improve habitat conditions, and to reintroduce a northern leopard frog population to the Columbia National Wildlife Refuge.
Northern leopard frogs in Washington have unique genetics traits. Genetic testing on northern leopard frogs found in the Spokane area indicated they are not native to Washington, but likely captive frogs released illegally. These frogs may carry disease and alter the unique genetics of the native northern leopard frogs.
Description and Range
The northern leopard frog is a medium to large (3 to 4 inches in length) semi-aquatic frog with a slender body, thin waist, long legs and smooth skin. The dorsal (topside) color is brown or green with distinct round or oval dark spots in two to three irregular rows. The spots typically have a light border. The ventral color (underside) is cream or white with no markings. Learn more about how to identify this species and more information in the Washington Herp Atlas.
Ecology and life history
Northern leopard frogs are semi-aquatic, requiring both aquatic and terrestrial habitats. Breeding occurs in shallow, still water sites. Typically these areas are exposed to sunlight and have thin but sturdy vegetation stems for egg attachment. In central Washington, breeding takes place in April. Males vocalize with a low snore followed by low grunts to attract females to breeding locations.
A grapefruit-sized egg mass is deposited just below the water surface and attached to vegetation. Eggs may hatch within a few days or weeks depending on water temperature. Tadpoles forage mainly on algae and detritus, and complete metamorphosis in 60 to 90 days. Newly metamorphosed frogs emerge from ponds starting in mid-July.
During the active season, leopard frogs eat a variety of insects and small frogs. They forage on pond edges, damp meadows, marshes, fields, irrigation ditches, and scrublands.
They typically overwinter under water, and require deep, well-oxygenated water that does not freeze solid to the sediments.
Northern leopard frogs may be preyed on by many species throughout their life history, but the most common are likely mustelids, bullfrogs, and fish.
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. The last known population of northern leopard frogs in Washington is located in the Columbia Basin Wildlife Area.
Sensitivity to climate change
Limited information existsregarding the sensitivity of Northern leopard frogs to climate change. They may experience some sensitivity to potential increases in temperature, which could lead to earlier timing of mating and breeding. Their sensitivity will be increased by potential climate-induced changes in their pond habitat. Adults need deep water, seasonal ponds, and wetlands for breeding habitat and potential warmer, drier conditions could lead to declines in available breeding habitat. Non-breeding active season habitat for Northern Leopard Frog consists of herbaceous riparian habitat with sufficient surface moisture; this habitat, which is likely the most vulnerable to climate change because of more extreme summer drying, is likely to affect Northern Leopard Frog choices of non-breeding active season habitat, especially during summer conditions - where more severe contraction of that habitat is anticipated. Whether Northern Leopard Frogs might then utilize aquatic habitat more frequently during this season is unclear. It is also unclear how such a shift might exposure NLF to a different predator set. Drier conditions could even lead to localized population extinctions if breeding ponds become too shallow or disappear completely.
Exposure to climate change
- Increased temperatures
- Changes in precipitation
- Altered hydrology >Reduction in non-breeding active season habitat in summer
Rules and Seasons
Due to the significant reduction in range and abundance of leopard frogs in Washington, and the continued threats to the remaining occupied sites, leopard frog were classified as an endangered species in Washington in 1999. The law protects endangered species and prohibits them from being hunted, taken maliciously, harassed, or possessed. This is for all life stages including adults, juveniles, tadpoles, and eggs. Keeping this species as a pet in Washington is also prohibited because species native to the state cannot be kept in captivity. The only exceptions are for zoos, educational centers, rehabilitation facilities, and research facilities that receive permits from WDFW.
Conservation Threats and Actions Needed
- Invasive and other problematic species
- Threat: Non-native aquatic species including American bullfrogs, mosquito fish and other non-native predatory game fish. Bullfrogs are predatory for all life stages of northern leopard frogs.; mosquito fish prey on amphibian egg masses and tadpoles. Non-native predatory game fish, such as bass, prey on the frogs and tadpoles.
- Action Needed: 1. Remove mosquito fish from ponds previously occupied by northern leopard frogs. 2. Prevent introduction of non-native fish to ponds occupied by northern leopard frogs. 3. Manage habitat to favor this frog but not favor bullfrogs and fish (example, create seasonal ponds). 4. Create and maintain barriers such as dikes that prevent non-native fish from entering ponds occupied by this species.
- Threat: Unknown impacts to population from disease.
- Action Needed: Additional disease monitoring is necessary to determine the extent of the disease threat in the Northern Leopard Frog Management Area on the Columbia Basin Wildlife Area.
- Threat: Wetland succession and tall emergent vegetation encroachment (example, reed canary grass, phragmites, and non-native cattails) reduces suitability of habitat.
- Action Needed: Set back succession, reduce tall emergent vegetation and encourage short emergent cover through chemicals and mechanical treatments.
- Fish and wildlife habitat loss and degradation
- Threat: Loss of suitable habitat due to water management in the Potholes Reservoir (drawdowns, backups).
- Action Needed: Create and restore breeding habitat (seasonal ponds).
- Agriculture and aquaculture side effects
- Threat: The Odessa Supplemental Feed Route will influence water levels in Potholes Reservoir and may impact the amount of suitable habitat in the Northern Leopard Frog Management Area on the Columbia Basin Wildlife Area.
- Action Needed: 1. Maintain suitable habitat to allow for dispersal and movement. 2. Monitor population. 3. Pursue opportunities to establish new populations. 4. Use adaptive management to deal with the high level of uncertainty regarding potential habitat changes.
See the Climate vulnerability section for information about the threats posed by climate change to the northern leopard frog.