Northern Prairie Wildlife Research Center
The 10 species are shown to fall along a natural ordination reflecting different life history characteristics. Average values of indices of r- and K-selection indicated that pintail, mallard, blue-winged teal, and shoveler have the most features associated with unstable or unpredictable environments. Gadwall, American wigeon (Anas americana), and green-winged teal (Anas crecca) were intermediate, and attributes of the diving ducks were associated with the use of stable or predictable environments.
Some species—notably mallard, gadwall, blue-winged teal, redhead, and canvasback—tend to fill available breeding habitat first in the central portions of their range, and secondly in peripheral areas. Other species— American wigeon, green-winged teal, northern shoveler, northern pintail, and lesser scaup—fill their habitat in the order it is encountered during spring migration.
Age and sex classes within species vary in their settling pattern. Some of this variation can be predicted from the mating systems of ducks in which breeding females, especially successful ones, have a greater investment in habitat resources and are more likely to return to the same area in subsequent years.