This IBA includes 23 miles of river recognized by Ohio's Wild and Scenic River program. The lower Grand River includes gorge areas with hemlock ravines in tributaries, a harbor, state park, county parks, hemlock ravines, riparian corridor, beach grasses/dunes, lakeshore, restored wetland, and deciduous forests. Reservations owned by Lake Metroparks protect some of the significant habitat, but there is also much private land.
The hemlock ravines associated with the main river corridor support populations of many northern breeders and typical local forest-nesting birds. The entire area exhibits high diversity and density of priority species. The Lake Erie shore sites are among the top three migrant traps in the state. Bald Eagles nest along the Grand River.
Big Creek Park includes large tracts of mature beech-maple forest, which provide nesting habitat for forest-interior nesting neotropical songbirds, as well as a northern hemlock-birch forest association attracting nesting northern songbirds (Dark-eyed Junco, Black-throated Green Warbler, Blue-headed Vireo, Winter Wren and possibly others-more survey work is needed). Since the early 1990s, this park has featured a rich assemblage of neotropical birds during the breeding season. Bird records come from annual spring bird walks by various naturalists, with quarterly bird reports submitted to 'The Ohio Cardinal' and the 'Cleveland Bird Calendar'. Notable probable breeding species include: Broad-winged Hawk and Red-shouldered Hawk, Pileated Woodpecker, Yellow-bellied Sapsucker (documented nearby), Yellow-billed Cuckoo, Blue-headed Vireo, Yellow-throated Vireo, Winter Wren (occasional-rare), Blue-winged Warbler, Chestnut-sided Warbler, Black-throated Green Warbler, Cerulean Warbler, American Redstart, Hooded Warbler, Louisiana Waterthrush, and Dark-eyed Junco.
Girdled Road Reservation is home to 16 species of nesting state-listed birds and 15 species of birds considered uncommon-rare regionally. Endangered species associated with the site include Yellow-bellied Sapsucker and Golden-winged Warbler. Threatened species include Least Flycatcher and Dark-eyed Junco.
Grand River Terraces, one of the few remaining hemlock swamps left in Ohio, is home to a number of rare and state-listed bird species; those found in this habitat include Yellow-bellied Sapsucker, Hermit Thrush, and Northern Saw-whet Owl.
The hemlock ravines of the Lake County portion of the Grand River watershed hold a significant percentage (as many as 50%) of the state Dark-eyed Junco breeding population. The watershed also has populations of other representative northern nesters, such as Black-throated Green Warbler, Magnolia Warbler, Canada Warbler, Veery, Saw-whet Owl, and Winter Wren.
Headlands Dunes State Nature Preserve is an important migrant trap, with exceptional variety of birds, including the following migrants: American Bittern, Least Bittern, Northern Harrier, Peregrine Falcon, Merlin, Virginia Rail, Sora, Common Moorhen, Piping Plover, Common Tern, Short-eared Owl, Northern Saw-whet Owl, Sedge Wren, Northern Shrike, Golden-winged Warbler, Grasshopper Sparrow, Henslow's Sparrow, etc. Monitored weekly, the area has over 300 species seen. Headlands Dunes State Nature Preserve is designated Critical Habitat for Piping Plover.
Hell Hollow Wilderness Area has hosted fifteen species of nesting state-listed birds. It is important not only for the number of species, but the total numbers of individuals nesting. Hemlock ravines harbor state-listed birds. On several occasions in excess of 30 pairs of Dark-eyed Juncos have been found. Endangered species include Yellow-bellied Sapsucker, while threatened species include Barn Owl, Least Flycatcher, Hermit Thrush, and Dark-eyed Junco. In addition, 15 other species considered rare-uncommon regionally have also been found.
Mentor Marsh regional ecosystem, with its diversity of habitat, supports a wide variety of both migratory and nesting birds. Within this area lie nearly 1,000 acres of marshland, a habitat type that has become rare in Ohio. There is also swamp forest, barrier beach and dunes, all of which are publicly owned. The Ohio coastal management program has determined this land and its attendant watershed as a special area for management because of its unique location and habitat types.
The private property east of and adjacent to Headlands Dunes State Nature Preserve is a concentration point for migratory passerines during spring and fall migration. It involves more appropriate scrub habitat than the adjacent Headlands Dunes SNP and has a higher concentration of birds during migration.
The former Diamond Shamrock site is a possible Northern Harrier breeding site. Significant wintering areas for Merlins, Rough-legged Hawks, and Northern Shrikes exist here. There is evidence the threatened Upland Sandpiper has nested here. Another threatened species associated with the site is Least Flycatcher.
Regular bird walks at Headlands Beach and in Metroparks for over 20 years provide accurate information on the bird species. Lake and Geauga County Metroparks and the Cleveland Museum of Natural History, among others, are advancing the cause of habitat conservation along the corridor, which is under a general threat of development with attendant fragmentation. Fragmentation
is problematic surrounding the parks and along with siltation may have a detrimental effect of the streams of the corridor. Invasive species (e.g. garlic mustard, Japanese knotweed, buckthorn, phragmites, purple loosestrife, and reed canary grass) along the corridor are being managed in the Lake and Geauga Metroparks.
The Diamond Shamrock site is a former industrial site and is considered highly polluted. Given the number of top-level predators found on the site, it is an important area.
Mentor Marsh area lies in a highly developed suburban area and is experiencing all the attendant pressures of this development: habitat loss, nearby housing, pesticide and herbicide usage by nearby homeowners, and placement of sewer lines with drainage into the marsh. While the ecosystem has suffered greatly from the invasion of phragmites, on occasions when fire has cleared areas a viable diverse native seedbed has been documented. The ecosystem has been selected for a strategic area management program by the Ohio Coastal Management Program of ODNR.