Oregon Spotted Frog (Rana pretiosa)

Small brown and red frog with dark spots crouched in water and grass
Oregon spotted frog
Category: Amphibians
State status: Endangered
Federal status: Threatened
Vulnerability to climate change (More details)

Moderate-
High

If you see this species, please share your observation using the WDFW wildlife reporting tool or email us at  wildlife.data@dfw.wa.gov. Be sure to include a photo of the species for verification and location (latitude/longitude coordinates) of your observation. 

The Washington State status is based on the rarity of the species. Human-caused stressors include wetland loss and alteration, loss of disturbance processes that set back succession, introduction of non-native/invasive flora and fauna and alteration of creek and river channels.  Only six watersheds are currently known to be occupied in Washington.  Within a watershed, most breeding populations are small and many are isolated from other breeding populations.  They require breeding sites in shallow water with short vegetation and full sun exposure.  This habitat type is rapidly lost to invasive grasses without management such as grazing, haying, mowing or restoration to native flora. Learn about living with frogs.

Description and Range

Physical description

The Oregon spotted frog is a medium to large (adults are 2 to 4 inches snout to vent in length) aquatic frog. The dorsal color is olive brown to brick red, with black spots. See the Washington Herp Atlas for more details about this species, including description of tadpoles.

Ecology and life history 

An Oregon spotted frog floating just below the water
Brome McCreary - US Geological Survey

This species is highly aquatic and rarely found away from water.  Extant populations occur in large shallow wetland systems associated with a stream or stream network.  Breeding habitat is in seasonally flooded margins of wetlands and areas of extensive shallows (approximately 6 to 8 inches deep). Waters that remain aerobic and do not freeze to the sediments are necessary for winter survival in areas subject to freezing.  Beaver impounded systems appear to provide many of the habitat requirements of this species. Radio-telemetry and mark-recapture studies have revealed that Oregon spotted frogs are relatively sedentary during the summer (driest period) and remain active underwater during the winter.

Oregon spotted frogs eat mostly insects. Tadpoles eat algae and detritus (organic material) in the aquatic environment.  

These frogs are communal breeders that return to the same breeding areas each year. They require breeding sites in shallow water with short vegetation and full sun exposure. Breeding occurs in February and March, and times can differ depending on location, elevation, and water temperatures. Egg masses are placed in areas where they receive little or no shading from vegetation. Embryos take approximately three weeks to develop to hatching. Tadpoles transform in mid-summer of their first year.

Non-native predatory fish and American bullfrogs prey on Oregon spotted frogs.  

Geographic range

The historical range for Oregon spotted frogs in Washington is the Puget Trough Ecoregion and the southern extent of the Eastern Cascades Ecoregion in Whatcom, Skagit, Thurston, Skamania, and Klickitat counties. Current occurrences are in the Sumas River, Black Slough, Samish River, upper Black River drainage, lower Trout Lake Creek drainage, and the Conboy Lake and Camas Prairie in the Outlet Creek drainage.

For worldwide distribution of Oregon spotted frog and other species' information, check out NatureServe Explorer and the International Union for Conservation of Nature Red List.

Climate vulnerability

Sensitivity to climate change

Moderate-
High

Very limited information is available regarding the sensitivity of the Oregon spotted frog to climate change. Its main sensitivity is likely to be due to changes in pond and wetland habitat. This species is a warmer water marsh specialist that prefers shallow water ponds and vegetated pools connected to permanent water for breeding and tadpole development. Potential warmer and drier conditions could lead to alterations in or disappearance of shallow ponds and changes in vegetation, which could impact breeding and tadpole survival. In particular, it is likely to seasonally concentrate predators to a greater extent, and if those predators are warmwater exotics, it will increase the likelihood of predation on Oregon spotted frog life stages. Additionally, warmer temperatures could lead to increases in invasive warm water predators that prey upon Oregon spotted frogs, like bullfrogs and some invasive fish species, thus leading to potential population declines. Warmer temperature will also increase the active season for bullfrogs, which will reduce the time bullfrogs require to reach large body sizes, a situation that currently limits them somewhat in most areas of the Pacific Northwest. Increase bullfrog body size is likely to put the entire size distribution of post-metamorphic Oregon spotted frogs at risk.

Confidence: Moderate

Exposure to climate change

Moderate

  • Increased temperatures
  • Changes in precipitation
  • Altered hydrology >Increased temperature result in greater ecological release of exotics
Confidence: Moderate

Conservation

This species is identified as a Species of Greatest Conservation Need (SGCN) under the State Wildlife Action Plan (SWAP). SGCN-classified species include both those with and without legal protection status under the Federal or State Endangered Species programs, as well as game species with low populations. The WDFW SWAP is part of a nationwide effort by all 50 states and five U.S. territories to develop conservation action plans for fish, wildlife and their natural habitats—identifying opportunities for species' recovery before they are imperiled and more limited.
This species is identified as a Priority Species under WDFW's Priority Habitat and Species Program. Priority species require protective measures for their survival due to their population status, sensitivity to habitat alteration, and/or recreational, commercial, or tribal importance. The PHS program is the agency's main means of sharing fish and wildlife information with local governments, landowners, and others who use it to protect priority habitats for land use planning.

Conservation Threats and Actions Needed

  • Resource information collection needs
    • Threat: Lack of information on status and distribution.
    • Action Needed: Inventory areas that might still support this species and monitor known populations.
  • Invasive and other problematic species  
    • Threat: Invasive reed canarygrass. Oregon spotted frog oviposition habitat is located in seasonally flooded, shallow water (less than 6 inches), with short vegetation and full sun exposure. Reed canarygrass is invasive, has a dense growth, pattern and grows to over 5 feet tall.
    • Action Needed: Manage reed canarygrass either by keeping it short (mowing, haying, livestock grazing) or remove it.
    • Threat: Lack of disturbance to wetlands. Oregon spotted frog oviposition habitat is located in seasonally flooded, shallow water (less than 6 inches), with short vegetation and full sun exposure. This is typical of early successional wetland plant growth.
    • Action Needed: Create or mimic disturbance processes at sites occupied by Oregon spotted frogs. Examples include introducing beaver, use of fire, mowing, haying and/or grazing.  
    • Threat: Non-native predatory fish and American bullfrogs. These species prey on Oregon spotted frogs.  
    • Action Needed: Prevent non-native predatory fish and American bullfrogs from establishing populations at Oregon spotted frog occupied sites.  
  • Climate change and severe weather (See Climate vulnerability section above for more details about the threats that climate change pose to this species)
    • Threat: Drying of aquatic habitats occupied by Oregon spotted frog and subsequent changes to vegetation (expansion of trees, shrubs, and reed canarygrass, etc.).  
    • Action Needed: Prevent drying of wetlands and streams occupied b Oregon spotted frogs. Remove and manage trees, shrubs, and reed canarygrass in breeding habitat.
Closeup of an Oregon spotted frog peering just above the water's surface
Andy O'Connell

Our Conservation Efforts

Protecting the Oregon Spotted  Frog in Washington

The WDFW partners with U.S. Fish and Wildlife Service and Washington Department of Natural Resources to protect the Oregon spotted frog in Washington. Watch this video to learn about various  conservation efforts aimed at saving this species. See biologists conduct frog egg mass counts to get an idea of the number of breeding adults at a location and to better understand habitat use. Learn why habitat restoration for this species is important not only on public lands but on private lands, too, with the cooperation of private landowners who actively manage their property to help preserve this rare frog. 

Resources

WDFW Publications

Status report

Recovery plan

Fact sheet

Other