ENVIRONMENT YUKON






Birds

Monitoring breeding waterfowl

Significance

Yukon is the summer breeding home for more than 30 species of waterfowl and provides critical staging areas for birds migrating in the spring and fall.

Specific threats to Yukon waterfowl include:

  • Removal of standing dead wood (i.e., snags, standing dead trees) from areas along lake and river margins by commercial or small scale timber harvest removes potential nesting cavities and sheltering areas for waterfowl.
  • Changes in water regimes due to climate change or human activities (e.g., hydroelectric projects) may change the timing of ice formation and/or spring break-up. This has the potential to alter migration stopover sites for waterfowl either by preventing access (no open water in spring time) or by changing the accessibility of food (if water is too deep, waterfowl may not be able to reach submerged vegetation).
  • Disturbance of waterfowl due to increased human recreational activity (e.g., dogs running loose, boating, etc.) has detrimental effects on foraging efficiency and body fat acquisition. It is especially important during spring migration when there is often less time and less space (due to ice cover) for birds to acquire the resources they need to ensure successful reproduction.

This indicator provides information about waterfowl through an example of a diving duck (Lesser/Greater Scaup) and a dabbling duck (Mallard) in two survey areas in Yukon.

Monitoring waterfowl presence and abundance gives a good indication of the ecological health of an area, as waterfowl depend on wetland areas for food, nesting areas, and cover from predators.

What is happening?

There are two long-term survey areas for Yukon waterfowl:

  • Old Crow Flats is Yukon’s largest wetland for waterfowl and is considered globally significant. This 12,122 km2 area is almost completely free of development. It is used by the Vuntut Gwitchin First Nation for hunting, trapping and other cultural activities.
  • The Yukon Southern Lakes region features highly productive inlets and outlets of numerous large lakes that provide important waterfowl staging areas.

Overall, waterfowl populations in Old Crow Flats and the Southern Lakes region are stable, though there is annual variation in populations among species.

Diving ducks–Lesser and Greater Scaup

Diving ducks are named by their habit of diving for food. As well, they generally nest close to the water’s edges. The presence and abundance of diving ducks are indictors of water health.

Lesser and Greater Scaup are two diving duck species that are grouped for the purpose of this monitoring analysis since they are almost impossible to distinguish during aerial surveys. Scaup are in decline across North America with estimated populations approximately 43 per cent below the North American Waterfowl Management Plan (2012) conservation goal of 6.3 million.

  • At Old Crow Flats, the 2015 combined Lesser and Greater Scaup total adult population estimate was 44,627, 25 per cent less than the estimate from 2014. This is also 61 per cent less than the long-term average (1955-2014) of Scaup in this area (Figure 1).
Figure 1: Adult population estimate for Lesser and Greater Scaup at Old Crow Flats
  • The Southern Lakes ground surveys also show that Lesser and Greater Scaup are in decline. Although from 2012-2013 there was a 28 per cent increase in the breeding pairs of Scaup counted, since the start of the survey in 1991 there has been a decreasing trend.
Dabbling ducks-Mallard

Dabbling ducks walk well on land and can nest far from the water’s edge. They feed on grass and seeds on land, as well as algae, plants and insects in the water. The presence and abundance of dabbling ducks are indicators of the health of a wetland area.

Mallard is a common dabbling duck that is also extensively hunted in Canada; therefore, their populations are monitored. Across North America, Mallard populations are 26 per cent above the North American Waterfowl Management Plan target.

  • At Old Crow Flats, the 2015 Mallard total adult population estimate was 9,154, seven per cent more than the 2014 estimate. There is an overall increasing trend for Mallards (Figure 2).
Figure 2: Adult population estimate for Mallard at Old Crow Flats
  • The Southern Lakes ground survey shows that there is a modest long-term increasing population trend (over 15 years) for Mallards. Additionally, from 2012 to 2013 the breeding pair population of Mallards observed increased by 20 per cent.

Taking action

The North American Waterfowl Management Plan sets conservation goals for waterfowl across the continent; Yukon surveys contribute to information for continent-wide population monitoring.

References

Canadian Wildlife Service Waterfowl Committee. 2013. Population Status of Migratory Game Birds in Canada. Environment Canada, Gatineau, Quebec, Canada. Available from: http://www.ec.gc.ca/rcom-mbhr/B2A654BC-6B73-4D14-86CB-8D2FB3A70143/2013-November-report---EN---FINAL.pdf

North American Wetlands Conservation Council (Canada). 2013. North American Waterfowl Management Plan [cited 2016 Mar 3]. Available from: http://nawmp.wetlandnetwork.ca/

U.S. Fish and Wildlife Service. 1999-2015. Population Status [modified 2015 Oct 1; cited 2016 Mar 3]. Available from: http://www.fws.gov/birds/surveys-and-data/reports-and-publications/population-status.php

Data quality

Surveys are conducted annually in the Old Crow Flats wetland. In the Southern Lakes region, wetlands are surveyed along roadsides.

Old Crow Flats
Southern Lakes ground survey
  • Cooperative Yukon Roadside Waterfowl Breeding Population Survey
  • The survey consists of counts in a sample of wetlands, conducted four or five times from early May to mid-June.
  • This ground survey tracks trends only, not population estimates.
  • Ground surveys provide better accuracy for identification at the species level, but are limited by the requirement for road/foot access and are not suited to population estimates. Aerial surveys cover larger areas and are better suited for population estimates.