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Wye Marsh (ON015)


Wye Marsh (ON015)

Midland, Ontario

Latitude 44.713°N
Longitude 79.858°W
Altitude 180 - 185m
Area 29.54km²

Site Description

Wye Marsh is located in south-central Ontario, about 5 km east of the town of Midland. It is connected directly to Georgian Bay through the mouth of the Wye River, and as such, it experiences associated water level fluctuations. The wetlands are comprised mainly of cattails, small areas of fen, along with a larger area of open water (named Mud Lake). The community of Wyebridge is located at the upstream end of the wetland, and the approximate dimensions of the marsh are 1.5 by 4.5 km.


The Wye Marsh is well known for the Trumpeter Swan reintroduction program that the wildlife centre has been operating since the 1980s. Currently, there are 55 to 60 adult Trumpeter Swan that nest within the marsh. Trumpeter Swans are restricted to North America, where they occur in three relatively distinct populations: Pacific Coast (over 16,000 birds), Rocky Mountain (2,500 birds), and Interior (over 900 birds). The Wye Marsh population of Trumpeter Swans is the largest concentration in Ontario, and comprises a significant percentage of the interior population. Historical nesting of Trumpeter Swans in the Wye Valley has been documented through archaeological evidence.

In addition to Trumpeter Swans, a relatively large colony of Black Terns also nests at Wye Marsh, with as many as 61 pairs being present. Although a national population estimate is not available for this species, a regional study (Priority Migratory Bird Habitats of Canadas Prairie Provinces 1990) used a threshold of 50 for identifying sites of national significance. The nationally vulnerable Least Bittern nests in significant numbers, with 11 pairs (approximately 1% of the Canadian population) surveyed in 2000. Other marsh nesting species include American Bittern, Virginia Rail, Sora, and Marsh Wren, among others. A total of 222 species of birds have been recorded at this site, of which 64 have been confirmed as nesters.

Conservation Issues

The Wye Marsh Wildlife Centre is operated and managed by the Friends of Wye Marsh as a non-profit organization dedicated to maintaining the marsh and promoting awareness and conservation of the natural areas of Wye Marsh. They have played an important role in the efforts to reintroduce the swans within this Provincial Wildlife Area. Thus far, the greatest threat to the reintroduced swans has been lead poisoning from the ingestion of lead shot. The use of lead shot at this site (for hunting) has now been banned. Other threats to the marsh habitat at this site include Purple Loosestrife, which is a non-native, invasive species that out-competes other native vegetation that wildlife depends on. Agricultural development in the adjacent watershed has also influenced the habitat through increased sediment and nutrient loads. Historically, the marsh supported large stands of wild rice; now the vegetation is largely dominated by cattails. Both Ducks Unlimited and the Ontario Ministry of Natural Resources, as well as the Friends of Wye Marsh have had considerable involvement in the management of this marsh.

IBA Criteria Habitats Land Uses Potential or Ongoing Threats Conservation Status
Rusty Blackbird
Number Year Season