Population status

Gadwall
(Mareca strepera)

The Gadwall is primarily monitored in its core breeding area through the Waterfowl Breeding Population and Habitat Survey in western Canada, as well as the Waterfowl Breeding Population Survey of the Central Interior Plateau of British Columbia. The Gadwall popuation in Canada has shown a large increase since the early 1990s, following a period of prolonged drought in the 1980s. Gadwall populations are above their North American Waterfowl Management Plan goal in most surveyed areas (North American Waterfowl Management Plan 2012) and the population size in the traditional survey area is more than twice the objective of 1.5 million birds. The species is at an acceptable level relative to its national population goal. Detailed information on the population status of waterfowl species is available in the Population Status of Migratory Game Birds in Canada report (summarized version). To obtain a copy of the full version of this report, including tables and graphs, please contact ec.scf-oismiggibiers-cws-miggamebirds.ec@canada.ca.

 

Population goal and acceptable levels of variation

Species/groupGoalLower levelUpper level
CanadaLong-term average of the time series10th percentile of observed abundance (1970-2012)Not applicable

British Columbia Coastal Waterbird Survey

Additional information on: British Columbia Coastal Waterbird Survey

Table 1: Population trends by geographic area
Geographic areaTime PeriodAnnual Trend Table 1 - footnote 1 Limits
LowerUpper
British Columbia coast1999-2016-6.6-13.92.6
 

Waterfowl Breeding Population and Habitat Survey in Western Canada and the Northwestern United-States

Additional information on: Waterfowl Breeding Population and Habitat Survey in Western Canada and the Northwestern United-States

Table 2: Population trends by geographic area
Geographic areaTime PeriodAnnual trend Table 2 - footnote 1   Table 2 - footnote 2 Limits
LowerUpper
Total survey area Select to view graph of the geographic area: Total survey area 1955-2017; Waterfowl Breeding Population and Habitat Survey in Western Canada and the Northwestern United-States1955-20173.12.83.4
Canadian Prairies Select to view graph of the geographic area: Canadian Prairies 1955-2017; Waterfowl Breeding Population and Habitat Survey in Western Canada and the Northwestern United-States1955-20172.92.63.3
Western Boreal Forest Select to view graph of the geographic area: Western Boreal Forest 1955-2017; Waterfowl Breeding Population and Habitat Survey in Western Canada and the Northwestern United-States1955-20170.5-0.41.2
 

Cooperative Yukon roadside Waterfowl Breeding Population Survey

Additional information on: Cooperative Yukon roadside Waterfowl Breeding Population Survey

Table 3: Population trends by geographic area
Geographic areaTime PeriodAnnual trend Table 3 - footnote 1   Table 3 - footnote 2 Limits
LowerUpper
Southern Yukon Select to view graph of the geographic area: Southern Yukon 1991-2016; Cooperative Yukon roadside Waterfowl Breeding Population Survey1991-20160.600.3
 

Waterfowl Breeding Population Survey of the Central Interior Plateau of B.C.

Additional information on: Waterfowl Breeding Population Survey of the Central Interior Plateau of B.C.

Table 4: Population trends by geographic area
Geographic areaTime PeriodAnnual trend Table 4 - footnote 1   Table 4 - footnote 2 Limits
LowerUpper
British -Columbia Central Plateau2006-2017-3-9.52.8
 

References