IBA Douglas Marsh
Douglas, Manitoba
Site Summary
MB002 Latitude
Longitude
49.807° N
99.497° W
Elevation
Size
335 m
151.52 km²
Habitats:
deciduous woods (temperate), scrub/shrub, sedge/grass meadows, freshwater marsh, bog
Land Use:
Rangeland/pastureland, Tourism/recreation, Water management
Potential or ongoing Threats:
Agricultural pollution/pesticides, Disturbance, Drought, Drainage of wetlands, Fire, Grazing, Intensified management, Other environmental events, Recreation/tourism
IBA Criteria: Globally Significant: Congregatory Species, Nationally Significant: Threatened Species
Conservation status: IBA Conservation Plan written/being written
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Site Description
Douglas Marsh is located east of the city of Brandon Manitoba; the Trans-Canada Highway runs along the north border and the community of Shilo lies to the south. This large and shallow fen, which acts as a catchment basin for the surrounding agricultural land, has little open water except at its western end. Sedges and grasses are the dominant vegetation types, but two gentians that are rare in Manitoba, Felwort and Star Gentian, are also found here. On the eastern side of the marsh lies the willow-shrub edge of the Carberry Sandhills.
Birds
Birders and guided bird groups come to Douglas Marsh to see Yellow Rails where the extensive fens of the western side of Douglas Marsh hold very large numbers of the nationally vulnerable species. This rail is one of the most secretive species of birds, and so accurate surveys are difficult. Nonetheless, in 1995 a minimum of 500 pairs were thought by some to breed at Douglas Marsh. It should be noted that this number was arrived at by extrapolation. Another observer recorded 108 calls in a five-minute period in June, 1993. Although a precise estimate is not known, most observers agree that this site is significant for Yellow Rail and indeed may hold the largest colony of Yellow Rails south of the Hudson Bay Lowlands.

Several other marsh and grassland species are known to occur in the marsh. Virginia Rail and Sora both nest here and Le Conte’s Sparrow and Nelsons Sparrow are also regularly encountered in large numbers during the breeding season. Sedge Wrens are found in the hundreds and nest throughout the marsh, and Mallards are common breeders.




IBA Criteria
SpeciesT | A | I Links Date Season Number G C N
Loggerhead Shrike 2013 SU 1
Yellow Rail 1995 SU 1,000
Note: species shown in bold indicate that the maximum number exceeds at least one of the IBA thresholds (sub-regional, regional or global). The site may still not qualify for that level of IBA if the maximum number reflects an exceptional or historical occurrence.
 
Conservation Issues
Natural elements such as drought and succession of plant species all have an impact on this marsh. Factors caused by humans that are or could affect the marsh include: an increase in agriculture, the spraying of herbicides, fire management, ecotourism, highway expansion and overgrazing by cattle. Some of these actions could severely impact the functioning of the marsh ecosystem, and the survival of the Yellow Rails. For example, Highway #340, which runs through the site, was redeveloped back in the early 2000’s. Ecotourism is also a threat since occasionally people trample rail habitat and nest sites. When making development decisions, care must be taken to maintain the natural features and hydrology of the marsh, and to minimize the disturbance of the birds.

A newer threat is high water levels, primarily as a result of a prolonged wet cycle across southern Manitoba. This has resulted in the flooding of Yellow Rail habitat. Additionally, beavers have been known to block culverts. Since the rails need shallow water less than 20 cm deep, even moderate flooding of this kind can make habitat unsuitable.


The IBA Program is an international conservation initiative coordinated by BirdLife International. The Canadian co-partners for the IBA Program are Bird Studies Canada and Nature Canada.
   © Bird Studies Canada