Small numbers of wetland birds are recorded along BBS routes throughout most of North America. The largest number of species are found in the prairie provinces of Canada and portions of North Dakota, commonly known as the "prairie pothole" region. However, similar numbers of species may occur locally in Florida, eastern Texas-southern Louisiana, and locally in portions of the western U.S.
Along BBS routes, wetland birds tend to be increasing from the Rocky Mountain region into the Pacific Northwest, in the Great Lakes states/provinces, and in the central United States from Texas north to Kansas and Louisiana north to Minnesota. Declining trends prevail in eastern North America from Kentucky and Virginia south to Florida, and in the "prairie pothole" region- especially North Dakota.
The BBS data indicate that nearly 63% of wetland bird species have increasing trends, the highest percentage of increasing species of any group. However, these trend estimates should be viewed with considerable caution since wetland birds tend to be very poorly represented along most BBS routes. Their preferred habitats are generally scarce along roads in most portions of the continent. Additionally, many wetland birds are very secretive and poorly censused by the BBS methodology. Since wetlands have been disappearing across North America throughout this century (Tiner 1984), the availability of suitable habitats may be the limiting factor for wetland birds in many states and provinces.
We note that waterfowl and other game species are monitored with extensive surveys by the U. S. Fish and Wildlife Service and the Canadian Wildlife Service as part of the process of setting annual harvest regulations. These surveys extend well to the North of the BBS survey area, and provide a yearly estimated population index for many species. We recommend that readers interested in waterfowl population dynamics consult the Waterfowl Status Reports produced each year by the Office of Migratory Bird Management of the U. S. Fish and Wildlife Service.
Tiner, R.W., Jr. 1984. Wetlands of the United States: current
status and recent trends. U.S. Fish and Wildl. Serv.,
Washington, D.C. 59 pp.