Patapsco Valley IBA is a forested corridor extending for more than 50 km along the Patapsco River and tributaries through Carroll, Baltimore, Howard and Anne Arundel Counties and is one of the largest contiguous natural areas in Maryland?s Piedmont region. Mature oak-hickory forest cloaks the steep valleysides along the Patapsco River. Other well-represented habitats include riparian forest, serpentine grassland, pine barrens and shrub/old-field, each supporting distinctive bird communities. The great majority of the site consists of protected areas, including four units owned and managed by Maryland DNR (Patapsco Valley State Park, Soldier?s Delight Natural Environment Area (NEA), Morgan Run NEA, Hugg-Thomas WMA) and one owned and managed by the City of Baltimore (Liberty Reservoir CWMA). The site also includes small areas of adjacent private lands. Soldier?s Delight NEA contains one of the largest remaining serpentine barrens in the eastern United States and is home to 39 species of rare, threatened and endangered plants as well as rare insects, rocks and minerals.
Patapsco Valley supports particularly diverse bird communities within two species assemblages, Forest-Interior Dwelling Species (FIDS) and shrubland birds. FIDS are birds defined by Maryland DNR as requiring large, intact patches of forest habitat - 23 species of FIDS breed regularly, with the highest diversity in the McKeldin Area of Patapsco Valley State Park. Two WatchList species, Cerulean Warbler and Wood Thrush, occur in significant numbers in the forest. The diverse shrubland bird communities at Soldier's Delight NEA and Morgan Run WMA include two species on the WatchList, Prairie Warbler and Blue-winged Warbler. Soldier's Delight hosts the last remaining population of Whip-poor-will's in Baltimore County.