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Gadwall, Ron Ridout
Photo © Ron Ridout

Photo: Ron Ridout
Breeding evidence - Gadwall
Breeding evidence
Probability of observation - Gadwall
Probability of observation
Elevation plot - Gadwall
Elevation plot

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Gadwall
Anas strepera
Landscape associations:

Click on plot to view table of mean abundance
Elevation range:
0 - 1112 m
Conserv. status:
Not at risk
Global importance
of B.C. population:
6
Number of squares
ConfirmedProbablePossiblePoint counts
65 79 60 32
Long-term BBS trends
RegionYearsTrend (conf. interv.) Reliab.
Brit. Col.1970 - 2012 9.92 (2.31 - 19.4)Low
Canada1970 - 2012 2.62 (0.072 - 4.81)Medium

Mean abundance by region

Bird Conservation Regions [plot]
NW Interior ForestBoreal Taiga PlainsGreat BasinNorthern RockiesN. Pacific Rainforest
 0.01 0.310.25 0.18
Ecoprovinces [plot]
N. Boreal Mountains Taiga Plains Boreal Plains Georgia Depression Sub-Boreal Interior
 0.02 0.010.18  
S. Interior Mountains Central Interior Southern Interior S. Alaska Mountains Coast & Mountains
0.040.39 0.19   

Mean abundance by habitat [plot]

Boreal Altai Fescue AlpineBoreal White and Black SpruceBunchgrassCoastal Douglas-fir
 0.010.730.46
Coastal Mountain-heather AlpineCoastal Western HemlockEngelmann Spruce -- Subalpine FirInterior Cedar -- Hemlock
 0.09 0.04
Interior Douglas-firInterior Mountain-heather AlpineMontane SpruceMountain Hemlock
0.3   
Ponderosa PineSpruce -- Willow -- BirchSub-Boreal Pine -- SpruceSub-Boreal Spruce
0.46   

Characteristics and Range This subtly elegant dabbling duck has undergone a more dramatic 20th Century expansion of its global range across North America, Europe and Asia, than almost any other species of waterfowl. In North America, this has occurred through natural expansion and numerous introductions. Here, its core breeding range remains the Prairie Pothole region, from where it migrates south to winter mainly around the Gulf Coast of the United States (Leschack et al. 1997). Breeding now occurs from the Alaska Peninsula and western basins through the Great Lakes to the Atlantic Coast, and wintering occurs across most of southern North America.

Distribution, Abundance, and Habitat Breeding is rather clustered in relatively discrete areas of southern, central and northeast British Columbia: the lower Fraser, Thompson-Nicola and Okanagan, Chilcotin and Peace rivers. The range expansion of the 20th Century noted by Campbell et al. (1990) appears to have continued slowly: breeding now extends to the western Chilcotin Plateau, the Southern Rocky Mountain Trench, and is more extensive in the Peace River lowlands and Central and Southern Interior ecoprovinces.

The Gadwall is not especially numerous as a breeding bird in British Columbia. The Probability of Observation model suggests that the Thompson River and Fraser-Chilcotin river junction areas may be of elevated provincial importance. Breeding occurs between sea level and 1,100 m.

A range of wetland habitat types are used for breeding, with freshwater and brackish marshes generally preferred, and lakes, wet grassland, farmland ditches and sewage lagoons also used. Nests are usually situated in tall vegetation, often on islands, and very well concealed (Campbell et al. 1990).

Conservation and Recommendations There are no conservation concerns for the Gadwall. Continued monitoring will help clarify the degree to which it is expanding its range in British Columbia.

Peter J.A. Davidson

Recommended citation: Davidson, P.J.A. 2015. Gadwall in Davidson, P.J.A., R.J. Cannings, A.R. Couturier, D. Lepage, and C.M. Di Corrado (eds.). The Atlas of the Breeding Birds of British Columbia, 2008-2012. Bird Studies Canada. Delta, B.C. http://www.birdatlas.bc.ca/accounts/speciesaccount.jsp?sp=GADW&lang=en [10 Dec 2018]

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