The tidal fresh reach of the York River begins near the confluence of the Pamunkey and Mattaponi Rivers and extends westward to below the crossing of Route 360. This area supports one of the largest complexes of brackish to tidal fresh marshes in North America. The surrounding landscape is home to the Pamunkey and Mattaponi Indian tribes and contains several historic plantations. Until recently, the area has experienced less pressure for residential development compared to other jurisdictions within the region. Uplands remain predominantly rural and are used for agriculture and forestry. The waterways support extensive forested wetlands.

{link:For a fact sheet on this IBA, including a map, click here|}

Ornithological Summary

The oligohaline and tidal-fresh marshes of the lower Pamunkey and Mattaponi Rivers likely support the largest population of King Rails and Least Bitterns in Virginia. These marshes also support thousands of staging Soras and Tree Swallows during fall migration and high concentrations of waterfowl during winter. Forested wetlands support several species of neotropical migrants during the breeding season and are important stopover habitats during fall migration. These patches support large communal roosts of mixed blackbirds during the winter including the Rusty Blackbird. The waterways support significant and growing populations of Bald Eagles and Osprey. The site has not been a major area of bird research and much remains to be learned about its appropriate role in bird conservation.

Conservation Issues

There are two primary threats that are currently of concern including 1) the loss of marshes to sea-level rise and 2) the conversion of open land to residential development. Over the past decade, the oligohaline marshes have begun to exhibit a transition in vegetational composition related to sea-level rise. Sediment deposition is not keeping pace with subsidence and sea-level rise causing a lowering of the marsh surfaces and a corresponding shift in the vegetation community. This drowning of the marsh will result in a shift in the associated bird community. Because this marsh type is rare within the region, changes will continue to be cause for concern. Until recently, the upland landscape within the area has remained rural with relatively little development pressure. Since 2000 there has been an increase in residential development, particularly along primary shorelines. Many of the species that depend on habitats within the area are sensitive to development.


This area has relatively few parcels of land within protected status with owners including The Nature Conservancy (Mattaponi River Megacomplex, Comberland Marsh Preserve), the Pamunkey Tribe, and the Mattaponi Tribe. However, large tracts of both upland and wetland in private ownership are under progressive management for wildlife including birds.


This area supports one of the largest complexes of brackish to tidal fresh marshes in North America. Extensive forested wetlands dominated by red maple cover a significant portion of the waterways within the IBA. Uplands remain predominantly rural and are used for agriculture and forestry, with a diversity of forests that range from mixed deciduous forests of oaks, hickories, maples and beech to loblolly pine plantations.

Land Use

Land use is primarily farming and forestry with an increasing component of residential and urban development.

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