Black River Unit protects fragile and unique natural habitats and their wildlife.

About the Unit

The Black River is an important tributary of the Chehalis River, which is itself the most intact lowland river system left in western Washington. The Black River Unit's boundary generally encompasses the northern portion of the Black River south of Black Lake.

The Black River Unit consists of a large, complex mosaic of wetland, riparian riparian
Definition of riparian habitat or riparian areas.

Learn more about riparian
, and upland habitats surrounding the low-lying river. These diverse habitats include river and tributary channels, locally rare and unique bog, shrub swamp, riparian forest, emergent marsh, seasonally flooded non-native grassland, dry non-native grassland, and mixed forest. Drainage from the nearby Black Hills creates Stony, Dempsey, and Waddell Creek tributaries, as well as many seeps and springs. This low-gradient, meandering river of tannin-stained, slow-moving, nearly silt-free water flows southwesterly with a floodplain that is subject to frequent surface flooding during winter and spring.

Within the boundary of the Unit, there is spawning and rearing habitat and migration corridors for steelhead, cutthroat trout, and coho and Chinook salmon. 150 species of migratory birds, including waterfowl and neotropical songbirds, are found here. The Olympic mudminnow, a state-endemic and state species of concern, survives in the Unit. The federally threatened and state endangered Oregon spotted frog survives here thanks to the complex system of wetlands and connections to the river. Some of the largest Oregon spotted frog population in Washington State are found here.

Management programs on the Unit are focused on protecting and enhancing the unique habitats for fish and wildlife, including rare or declining species, migratory birds, anadromous salmonids, amphibians, and other wildlife. Land areas within the Unit are currently closed to public access.

Our History

In 1980, a Service wetland inventory program identified the Black River wetland system as an important habitat in Washington State. This intact, low-lying river system retained unique wetland bogs in a mosaic of natural wetland habitats. Thurston County identified and designated this area as “natural” in its Shoreline Management Plan. Identified in the Service’s Black River Swamp Preserve Design in1992, a clear description of the habitats describes the unique, relatively wild character and natural features of the wetlands south of the Black Lake. The document begins the discussion of habitat protection and management opportunities for the area. 

In an early land acquisition effort to protect the river corridor and surrounding floodplain wetlands, The Nature Conservancy acquired 320 acres in 1993 to manage the land as a nature preserve. The following year, the Pacific Coast Joint Venture (now known as the Pacific Birds Habitat Joint Venture) identified portions of the Black River in need of protection in their annual strategic plan. Members of the public and nongovernmental organizations advocated for the establishment of a refuge. A preliminary project proposal was developed by the Service in 1993, outlining habitat protection options and proposing an acquisition boundary. 

The Black River Unit of Billy Frank Jr. Nisqually National Wildlife Refuge was authorized in 1996; and the Unit was established with the purchase of the first parcel of land in 1998. Land purchases were made with funding from the Land and Water Conservation Fund and the Migratory Bird Conservation Fund. Community outreach efforts with landowners and willing sellers in the area continue today.


Birds of Management Concern (BMC) is a subset of all species protected by the Migratory Bird Treaty Act (50 CFR 10.13) and includes those which pose special management challenges due to a variety of factors (e.g., too few, too many, conflicts with human interests, or societal demands). The Unit provides breeding, wintering, and stopover habitat for some birds identified as BMCs with primary importance in the region and includes those species that can usually be observed using habitats within the Unit. Some of these species are: greater white-fronted goose (Pacific population), cackling and Pacific populations of Canada goose, gadwall, American wigeon, mallard (western population), northern shoveler, northern pintail, American green-winged teal, double-crested cormorant, bald eagle, peregrine falcon, Virginia rail, Caspian tern, and rufous hummingbird.

The Unit manages habitat for federally threatened and state endangered Oregon spotted frogs. State species of concern Olympic mudminnow as well as steelhead, cutthroat trout, and coho and Chinook salmon are found in the Black River and tributaries.

Roosevelt elk are commonly seen in parts of the Unit. Some are afflicted with the debilitating elk hoof disease that causes abnormal hoof growth and lameness. We cooperate with Washington State University and Washington Department of Fish and Wildlife researchers to learn more about the disease and potentially how to control it.

Management Priorities

  • Land and water protection: We aim to increase habitat protection and connectivity to reduce habitat fragmentation; improve water quality, and act to sustain and restore priority species and habitats in the Black River system.

  • Habitat management and restoration: Most habitats have been altered by human actions and are in need of enhancement and restoration to improve functional values for fish and wildlife. We collect data to gain important information on key species and habitats to guide future management actions and benefit species such as the Oregon spotted frog.
  • Invasive species control: Invasive plant species degrade habitat quality for migratory birds, fish, amphibians, and many other forms of fish and wildlife. Nonnative animals may compete with native fish and wildlife for limited resources. We manage both invasive plant and animal species within the Unit, such as yellow flag iris, purple loosestrife, wild chervil, reed canary grass, and American bullfrog.
  • Visitor services and education: The Black River Unit has remained largely closed because of the fragmented nature of current land ownership. A project to construct a wildlife viewing pullout with wayside interpretive panels is under way.
  • Conservation partnership: Many different groups and agencies have been and are involved with the protection, restoration, and interpretation of lands and waters within the Black River corridor.

Spotlight on the Oregon Spotted Frog

For more than 20 years, no one reported seeing an Oregon spotted frog in the entire state of Washington. Once found from British Columbia, Canada, to northeastern California, it seemed they had vanished, victims of habitat loss, changes in water quality, invasive non-native bullfrogs, and other causes. But in 1990, a biological survey found the first Rana pretiosa verified since 1968 in Western Washington. Six years later, the area where they made the discovery was put under the protection of the U.S. Fish and Wildlife Service. This area is known as the Black River Unit, managed as part of the Nisqually National Wildlife Refuge Complex.

The frogs have black, irregular splotches on their backs with white spots within the splotches. Their eyes are greenish-gold. Compared to the more-common red-legged frogs, they have shorter snouts and shorter legs and toes with more webbing on the hind feet. They like where they live, generally sticking close to home and not traveling very far.

Oregon spotted frogs lay egg masses in February and March. The temperature of the water dictates when eggs are laid, with 8 degrees Celsius (46.4F) being prime. Egg masses are found in open or lightly brushy, shallow wetlands. There may be a wider range of spots the frogs like to use, including thick wet brush where humans find it hard to access for surveys.

The refuge monitors sites and manages breeding habitat in part by mowing and grazing. Invasive reed-canary grass can choke out good frog habitat if left unchecked. Since reed canary grass is nearly impossible to eradicate, so we manage it instead by mowing. We mow in autumn before the ground gets too soft from rain for the tractor. Mowing at this time prevents the grass from dying during winter and forming a standing mass. Instead, it re-sprouts short and green and offers food for waterfowl. This short form also lets the sun shine into the shallow water, warming it for February frog egg-laying. Frogs are able to use the managed habitat before the grass grows several feet tall by mid-summer.

One egg mass is laid for each female, fertilized by one or two males.  There may be 550-900 eggs in each mass. Masses are often laid together in the same area, forming a cluster. Because they prefer shallow water, there’s a risk that the site they use could dry up if the weather doesn’t cooperate; or the egg masses could freeze. The refuge has a permit in case of bad conditions to move egg masses or to make emergency habitat modifications, like creating a little water channel or removing grass clumps.

The hydrology of the Black River area is “flashy”—meaning the shallow water can change a lot in a short time. Frogs may lay eggs in a wet place that a week or two later is dry. Part of the problem is drainage ditches, used to convert the original wetland into pasture. Beavers are a real benefit in this kind of landscape. They can change the habits of a creek and encourage more spreading and flooding, which is good for frogs. Their dammed ponds hold water more reliably, and also hold back encroaching trees, maintaining the open habitat spotted frogs prefer.

Drainage ditches are certainly not the only way humans have changed the hydrology of the Black River. The Black Lake Ditch was dug in 1922, diverting water from the lake into the Percival Creek watershed. This changed the water flow for the Black River watershed, draining agricultural land south of the lake. Much of the water flowing into the Black River now is from groundwater rather than from the lake. 

Culverts and bridges, too, have created barriers to water flow and wildlife movement. County engineers are working with Service staff to look at replacing culverts with better designs.

Another way to maintain good frog habitat may enlist the aid of cattle. Cattle owners on neighboring property use fences to control where they want their cattle to graze. “Flash grazing” is when cattle are let into frog territory for a few weeks to chew down the grass where it’s too wet for tractors to mow.

There could also be a connection between frogs and elk. Elk create trails and wallows that hold water in winter. And they eat brush, helping to maintain the open, wet areas spotted frogs prefer.

Good habitat keeps the Oregon spotted frog going, but managing invasive species invasive species
An invasive species is any plant or animal that has spread or been introduced into a new area where they are, or could, cause harm to the environment, economy, or human, animal, or plant health. Their unwelcome presence can destroy ecosystems and cost millions of dollars.

Learn more about invasive species
like bullfrogs is also important. American bullfrogs belong east of the Mississippi River, but were introduced to waterways in the West in the early 1900s. They thrive in part by eating other frogs and their eggs, as well as almost anything else they can get into their gaping mouths.

Bullfrog control is essential for protecting Oregon spotted frogs. The refuge hires seasonal bullfrog technicians to work nights, spotlighting bullfrogs and dispatching them with gigs and air rifles. They also set out audio recorders that capture sound. A computer program helps search for bullfrog calls and gives an idea of where the invaders may be located.

The mission of the U.S. Fish and Wildlife Service begins with “working with others.” It is working with others that gives the Oregon spotted frog its best shot at survival. From county engineers to biologists at state and federal agencies, from frog-giggers to farmers to fascinated volunteers, and from beavers to cows, it takes a whole network of effort. As we gain more understanding of the needs of this unique amphibian, we learn about the ecosystem of which it, and we, are a part.