Large shallow bay of Lake Huron extending from Bay City to Au Gres to Wildfowl Bay.

An array of waterbird species use the Saginaw Bay Area as a migratory stopover site, wintering ground, and breeding ground. Large migratory congregations of the columbianus subspecies of Tundra Swans (as many as 12,220 individuals) have been counted in November. Other significant migrant waterfowl concentrations include 505 American Black Ducks (Nov. 2003), 1550 Mallards (Nov. 2003), 9125 Redheads (Nov. 2004), 1748 Common Goldeneyes (Nov. 2002). Merganser spp. counts as high as 25,150 and 15,570 and Scaup spp. counts of 21,570 and 22,710 have also been made.

Several important waterbird breeding colonies also exist within this IBA, including the Contained Disposal Facility (CDF) offshore of Bay City which supported the following numbers of nests during 1997-1999: 234 Common Tern, 324 Caspian Tern, 28,605 Ring-billed Gull, 243 Great Egret, and 480 Black-crowned Night-Heron.

Pitcher's Reef supports a small breeding colony of Black-crowned Night-Herons.

Eutrophication (nutrients), various forms of pollution including toxic substances, bacterial contamination, and sedimentation. Sources include sediment bedload and transport, industrial and municipal discharges, combined sewer overflows, contaminated sediments in the river and bay bottom, urban and agricultural nonpoint source runoff, old waste disposal sites, and atmospheric deposition.

This IBA sits within Michigan's largest area of untapped wind resources, and is being targeted for at least 2 wind projects in the imminent future, as well as one already in progress (Harvest Wind Farm). Efforts to mitigate harmful effects on the Tundra Swans and other waterfowl have been undertaken at the township commission level.