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Tiny Marsh (ON025)


Tiny Marsh (ON025)

Elmvale, Ontario

Latitude 44.606°N
Longitude 79.938°W
Altitude 200 - 205m
Area 25.10km²

Site Description

Tiny Marsh is located in southcentral Ontario, approximately six km northeast of the town of Elmvale, and approximately three km inland from Georgian Bay. The majority of the wetland is covered by cattail and meadow marsh communities, with a few small areas of open water. A small portion of the site is forested swamp. Tiny Marsh provides the headwaters for the Wye River, which flows into the Wye Marsh near Midland. The Wye Marsh has also been identified as an IBA.


Tiny Marsh supports significant numbers of several marsh bird species. Between 1993 and 1996, an average of 146 Black Tern nests was recorded, with peak totals of 156 in both 1993 and 1995. This is a substantial population for southern Ontario; a Canadian population estimate is unavailable, although a threshold of 50 pairs for significant colonies has been used in one other regional study (Priority Migratory Bird Habitats of Canadas Prairie Provinces - 1990).

Least Bitterns (nationally vulnerable) also nest at Tiny Marsh in significant numbers, with estimates of 12 to 16 being present (this would represent greater than 1% of the estimated national population). King Rails (nationally endangered) also occur at Tiny Marsh in small numbers (one or two), but it is not known whether they are regular inhabitants. In total, 250 birds have been recorded at Tiny marsh, including other marsh nesting species like Pied-billed Grebe, American Bittern, Sora, Virginia Rail, Common Moorhen, American Coot, Blue-winged Teal, among others.

Conservation Issues

Many of the native wetland plants at Tiny Marsh are threatened by Purple Loosestrife. This plant is a non-native species that is quite invasive and once established, out-competes the native vegetation. There is an ongoing program to remove it by hand. The marsh is jointly managed by the Ontario Ministry of Natural Resources, Ducks Unlimited and the M-T-M Conservation Association, a non-profit group of volunteers. It has been identified as a provincially significant (Class 1) wetland and is a Provincial Wildlife Area.

IBA Criteria Habitats Land Uses Potential or Ongoing Threats Conservation Status
Rusty Blackbird
Number Year Season
27 - 1202021Spring
40 - 602020Fall
25 - 302019Spring
30 - 502017Fall
35 - 1422016Fall
25 - 1162016Spring
King Rail
Number Year Season
Least Bittern
Number Year Season
Prothonotary Warbler
Number Year Season