Audubon: Birds & Science

Site Description:

One of the largest Important Bird Areas in Maryland, Southern Dorchester County IBA occupies approximately the southern half of Dorchester County, north to Taylors Island, Greenbrier Swamp, and the marshes and forests flanking the Chicawicomico River north to Route 50. It includes Hooper Island and Barren Island off its southwestern shore. Described as “The Everglades of Maryland” this site is notable for having the one of the largest contiguous areas of tidal marsh in the northeastern United States, with vast expanses of both brackish marsh and saltmarsh. Other habitats include loblolly pine, deciduous and mixed forest, which are becoming increasingly subject to tidal influence in southern parts of the site. Forests in the northern part, which is traversed by the Chicawicomico, Transquaking and Little Blackwater Rivers, are frequently flooded with freshwater. Two large protected areas lie at the heart of this IBA: Blackwater National Wildlife Refuge is Federally owned, and Fishing Bay Wildlife Management Area is owned by Maryland DNR. Other state-owned lands include, Taylors Island WMA and LeCompte WMA. Privately protected land includes TNC’s Robinson Neck Preserve and Farm Creek Marsh, which is owned by the Chesapeake Audubon Society. Most of the rest of the site is in private ownership.

Ornithological Summary:

Arguably one of the most important sites for bird conservation in Maryland, Southern Dorchester County supports significant populations of wintering waterfowl, raptors, marshbirds and forest birds. Some of the most celebrated avian inhabitants of this area include Bald Eagles and large flocks of wintering waterfowl. However, in terms of conservation priority it is the breeding birds of saltmarsh that are of greatest importance. This IBA derives its “globally important” status from two WatchList species that are also on Birdlife International’s Red Data list: Black Rail (Near threatened) and Saltmarsh Sharp-tailed Sparrow (Vulnerable), both of which nest in the high marsh zone. Other at-risk species nesting in the marshes include: American Black Duck, Least Bittern, Northern Harrier, King Rail, Common Moorhen, Seaside Sparrow, and the coastal plain subspecies of Swamp Sparrow, and the area supports the full complement of Maryland’s saltmarsh-nesting birds. Forests at this site also host breeding at-risk species, including: Chuck-will’s-widow, Red-headed Woodpecker, Brown-headed Nuthatch, Prairie Warbler, Prothonotary Warbler and Worm-eating Warbler. Bald Eagles breed and winter here in their greatest concentration in Maryland. More than 30,000 waterfowl spend the winter, with the most numerous species being Canada Goose, Snow Goose, Mallard, Black Duck, Canvasback and Tundra Swan.

Conservation Issues:

Blackwater-Fishing Bay Marshes faces a complex array of conservation issues, including loss of marsh habitat, urban sprawl, and habitat management challenges. Since 1938, 7,000 acres, more than a third of the marsh area, has been lost to erosion, caused mainly by nutria, a large rodent introduced from South America. The nutria literally eat the marsh out of existence, leaving open water in its place. A nutria eradication program implemented in recent years has been very successful and small pools in the marsh have begun revegetating. Audubon Maryland-DC is working with partners to ensure this effort continues and expands to nearby nutria problem areas. Over the long term ongoing sea-level rise threatens to increase the amount of tidal inundation of the marsh. Traditional burning of large areas of marsh continues annually and may impact marsh-nesting birds by removing the thatch (litter layer) in which many species nest. More research is needed on the effects of marsh burning. A planned development of 3200 residential units in the Little Blackwater River drainage to the north of this IBA may impact the marshes by altering patterns of flooding and drainage within the watershed and by reducing water quality.