Wildlife & Habitat

Occoquan Bay grasslands at sunset - Bill Wallen.

Wetland habitats cover about 50 percent of the refuge, and include wet meadows, bottomland hardwoods, open freshwater marsh, and tidally influenced marshes and streams. About 20 percent of the unit is upland meadows, with the remaining vegetated areas consisting of mature or second growth forest. The plant diversity of this refuge is outstanding in that over 650 plant species are known to be present.

  • Osprey

    Osprey in flight - Bill Wallen.

    Ospreys are one of the most common bird species seen at Occoquan Bay NWR during spring and summer. They return in early March to re-form pair bonds and establish breeding territories. Breeding pairs can be observed nesting on platforms located throughout the refuge. The nearby Potomac River provides ample foraging grounds for this bird of prey that feeds exclusively on fish. Around late-summer, the ospreys migrate south to the rivers, lakes, and coasts of Central and South America. Other birds of prey also share the resources the refuge provides, from the small American kestrel to the proud bald eagle.

  • American Woodcock

    American woodcock on nest - Richard Baetsen.

    The singing “sky dances” of the American woodcock can be witnessed at Occoquan Bay NWR beginning in February and can continue into June. This plump, forest-dwelling shorebird, takes advantage of the refuge’s shrubland habitats for their famous breeding displays and nesting. In the wet, woody areas of the refuge, the woodcock forage for earthworms by prodding the soil with their long bills. Keep an eye out for these perfectly camouflaged birds while walking the trails. Other bird species you may encounter in woodcock habitat include northern bobwhite quail, eastern towhee, and prothonotary warbler.

  • North American River Otter

    River otters on a frozen lake - Cindy Kreticos.

    Playful river otters roam the wetlands of Occoquan Bay NWR year-round. Otters, who are members of the weasel family, hunt at night and feed on fish, amphibians, and shellfish. Along the waterways, look for scent-markers, which can be piles of grass and scat that smell musty. Otters use these scent marks as a form of communication to other otters in the area. Beavers and muskrat also utilize the same habitat as otters. By finding “sign” of these species, know that they are present in the area, even if you don’t get the chance to actually see one.

  • Grasslands

    Grassland habitat - Bill Wallen.

    Many species call the refuge’s grasslands home at different seasons of the year. Dominated by a mix of warm season grasses, refuge grasslands provide breeding, migrating, and wintering habitat for birds, mammals, insects, and more. Sparrow and thrush species are a common occurrence throughout the year. Grassland breeding birds arrive at the end of April to set up territories. Waves of migrating songbirds, especially warblers, vireos, and fly catchers pass through in May to northern breeding territories and again in late summer when migrating south. Migrating monarch butterflies are a common sight in September and dragonflies can be observed throughout the summer months.

  • Wetlands

    Wetland habitat - Bill Wallen.

    Wetland habitats include wet meadows, a four acre pond, bottomland hardwoods, open freshwater marsh, and tidally influenced marshes and streams. Sensitive fern, marsh mallow, swamp rose, rushes, willows, and more provide diverse habitats for waterbirds and waterfowl, including the American bittern, great blue heron, wood duck, and belted kingfisher. Spring peepers, green frogs, spotted salamanders, painted turtles, and otters are common amphibians associated with wetland habitats throughout the refuge. The tidal marshes and submerged aquatic vegetation are important nursery habitats for freshwater, estuarine, and marine fish species.

  • Woodlands

    Woodland habitat - Katy Defonde.

    Forested areas along Marumsco Creek and a number of sloughs, creeks, and the river serve as transitional habitats between wetlands and grasslands. Dominant woody species include maples, oaks, persimmon, sweetgum, and northern arrowwood. The forested bands provide important habitat for migrant and resident species. Blue-grey gnatcatchers, golden-crowned kinglets, winter wrens, swamp sparrows, hermit thrushes, owls, and hawks call the woodlands home. Mature trees support nesting bald eagle and great horned owl pairs. Visitors may also encounter white tailed deer, red fox, and turkey.