Matchedash Bay is near the southern end of Georgian Bay, approximately five kilometres north of Coldwater and immediately to the east of of Waubaushene. The site is at the border of the Canadian Shield: the northern side of the marsh grades into rocky habitat, while the southern side grades into more fertile soil. The North River and Coldwater River meet here and widen to form extensive marshes and a bay, before flowing out to Georgian Bay. Less than half of the IBA is composed of open water, while most of the remainder is freshwater marsh. A Spike-rush, Eleocharis rostellata, which is rare in the province, has been recorded here, along with many other regionally rare wetland plants. Noteworthy reptiles include Blandings Turtles, Map Turtles, Milk Snakes and Pickerel Frogs. The Five-linked Skink, which has been designated as nationally vulnerable has also been recorded at this site.
A wide variety of breeding marshland birds have been recorded at Matchedash Bay. One of the more significant is the Least Bittern, a species designated as nationally vulnerable by COSEWIC (Committee on the Status of Endangered Wildlife in Canada). Currently, there are 17 pairs of Least Bittern breeding in the marshes, which may represent close to 2% of the estimated Canadian population.
King Rails (nationally endangered) have also been recorded at Matchedash Bay during at least two summers. It is not known whether this species is a regular nester, but even one pair would be nationally significant given the species rarity in Canada. Other noteworthy marsh birds that are known to inhabit this site include Black-crowned Night-Heron, American Coot, Caspian Tern, Black Tern (15 nests in 1991), Virginia Rail, American Bittern, Sedge Wrens, and Marsh Wrens.
During the spring migration, the bay hosts numerous species of waterfowl. Hundreds of Canada Geese, Mallards, Common Mergansers and Ring-necked Ducks have been recorded, as well as moderate numbers of Common Goldeneyes, Buffleheads, Northern Pintails, Hooded Mergansers and American Black Ducks.
Sedimentation associated with agricultural practices has been identified as a threat that may affect the marsh. The riparian areas along both the North River and Coldwater River are heavily grazed by livestock, contributes to this problem. Management practices, such as controlled access has been suggested as a way of mitigating this problem. This area is a Provincial Wildlife Area and is managed by the M-T-M Conservation Association, a non-profit group of volunteers.IBA Criteria Habitats Land Uses Potential or Ongoing Threats Conservation Status