Northern Prairie Wildlife Research Center
Values of the 2 indices of life history characteristics and their average are presented in Table 5. As predicted, the negative of the first index and the other index varied together (r = 0.683, P = 0.03). Because these indices covary, it is reasonable to combine them into a single measure corresponding to the r- and K-continuum. Average indices indicate that the pintail mallard, blue-winged teal, and shoveler show the most features associated with unpredictable environments (i.e., are the most r - selected). Gadwall, American wigeon and green-winged teal are intermediate, and the diving ducks are most associated with predictable environments (i.e., are toward the K-selected end of the continuum).
aFrom Stewart and Kantrud (1973); average permanence (cropland ponds = 2, seasonal ponds = 3, semipermanent ponds and reservoirs = 4) times -0.1.