Wertheim National Wildlife Refuge

Site Description

  • State: New York
  • County: Suffolk
  • Ownership: Federal


  • Big Fish Creek Impoundment: 35 acres
  • Big Fish Creek Sub-impoundment: 7 acres

Ecology and Management

Wertheim National Wildlife Refuge encompasses 2,572 acres along the southern shore of Long Island and is part of the Long Island National Wildlife Refuge Complex. The lands were acquired in 1947 via the Migratory Bird Conservation Act and the Refuge Recreation Act (Long 2006). Two adjoining impoundments (totally over 70 acres) occur on the refuge. They were constructed in the 1980s along a tidal creek on the back side of a salt marsh fringing Long Island Sound. Water levels are currently managed by draining slowly in the spring to expose mudflats for migrating shorebirds and shallow waters for herons, and then raising levels slowly in the fall for the wintering waterfowl migration. Historically, wildlife food plants such as millet were planted in the impoundments. Phragmites encroachment is a concern and is actively managed by refuge staff.

The impoundments are host to a wide assortment of migrant shorebirds, long-legged waders, and waterfowl during migration (Long 2006). Refuge biologists have also documented several state-listed birds using the impoundments, including Northern Harrier, Pied-billed Grebe, Peregrine Falcon, Bald Eagle, Common Tern, and Least Tern. At least one Federally-listed species (Long-eared Bat) has been documented on the site.


Both impoundments are subjected to flooding and occasional saltwater intrusion during exceptionally strong storms and high tides. For example, during Hurricane Sandy, the dikes overtopped leading to significant erosion. Wertheim, along with several other National Wildlife Refuge sites in the Northeast, is participating in a regional USFWS effort to assess impoundment vulnerability.

Human Value

The Long Island Wildlife Refuge Complex, of which Wertheim NWR is a part, is within a 2 hour drive of nearly 14 million people and is visited by nearly 500,000 people per year (Long 2006). The exact number of annual visitors to Wertheim NWR (or to the impoundments specifically) is unknown, but there are several popular nature trails frequented by wildlife photographers.


We are grateful to Monica Williams (Wertheim NWR) for providing helpful information used on this page.

Literature Resources

Below is a list of articles describing research occurring at or near the impoundments:
  • Kinneary, J. J. 1993. Salinity relations of Chelydra serpentina in a Long Island estuary. Journal of Herpetology 27:441-446.
  • Kinneary, J. J. 1992. The effect of water salinity on growth and oxygen consumption of snapping turtle (Chelydra serpentina) hatchlings from an estuarine habitat. Journal of Herpetology 26:461-467.
  • Long, D. J. Long Island National Wildlife Refuge Complex Comprehensive Conservation Plan. Washington, D. C.: U. S. Fish and Wildlife Service; 2006.
  • Marks, M., B. Lapin, and J. Randall. 1993. Element stewardship abstract for Phragmites australis. The Nature Conservancy, Arlington.
  • Plattner, D. M., M. W. Eichholz, and T. Yerkes. 2010. Food resources for wintering and spring staging black ducks. The Journal of Wildlife Management 74:1554-1558.
  • Rochlin, I., M. E. Dempsey, S. R. Campbell, and D. V. Ninivaggi. 2008. Salt marsh as Culex salinarius larval habitat in coastal New York. Journal of the American Mosquito Control Association 24:359-367.