A Critical Review of the Aerial and Ground Surveys of Breeding Waterfowl in North America.
FISH AND WILDLIFE SERVICE LAUREL MD OFFICE OF MIGRATORY BIRD MANAGEMENT
Pagination or Media Count:
The U.S. Fish and Wildlife Service and the Canadian Wildlife Service in cooperation with others have conducted an annual survey of breeding waterfowl throughout central Canada, the north-central United States, and Alaska since 1955. The area comprises more than 50 strata of habitats. Ducks are counted from aerial transects, and the counts are adjusted upward to account for birds that are not observed by aerial crews. These adjustments, called visibility correction factors, are developed from counts on the ground during which all waterfowl are assumed to have been detected. Counts on the ground are made of a subsample of the aerial survey. Visibility correction factors are calculated for each species and for each aerial crew. The total number of ducks by species and by strata is then calculated as the product of the observed density, the visibility correction factor, and the area of the strata.
- Stress Physiology
- Cartography and Aerial Photography