Interpreting Evidence of Depredation of Duck Nests
in the Prairie Pothole Region
Reference Area and Predator Species
The contemporary Prairie Pothole Region, including prairie and aspen parkland zones, extends from west central Minnesota and southeastern South Dakota to central Alberta and encompasses about 800,000 km2 (Fig. 1). Breeding ducks are distributed throughout the region (Bellrose 1980). Common species are American wigeon (Anas americana), gadwall (A. strepera), North American green-winged teal (A. crecca carolinensis), mallard (A. platyrhynchos), northern pintail (A. acuta), blue-winged teal (A. discors), northern shoveler (A. clypeata), canvasback (Aythya valisineria), redhead (A. americana), lesser scaup (A. affinis), and ruddy duck (Oxyura jamaicensis) (Bellrose 1980). All species customarily nest in uplands except canvasback, redhead, and ruddy duck, which customarily nest over water.
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| Figure 1. Contemporary Prairie Pothole Region with prairie and aspen parkland zones (adapted from Kiel et al. 1972 and Mann 1974). |
Nine species and 2 congeneric species-groups of predators with potential to destroy duck nests in the Prairie Pothole Region (Sargeant et al. 1993) are treated herein (hereafter called principal predators). The 9 species are coyote (Canis latrans), red fox (Vulpes vulpes), raccoon (Procyon lotor), striped skunk (Mephitis mephitis), American badger (Taxidea taxus), mink (Mustela vison), Franklin's ground squirrel (Spermophilus franklinii), black-billed magpie (Pica pica), and American crow (Corvus brachyrhynchos). The 2 congeneric species-groups are weasels (ermine [Mustela erminea] and long-tailed weasel [M. frenata]) and gulls (ring-billed gull [Larus delawarensis] and California gull [L. californicus]).
Other animals that may occasionally destroy duck nests at widely scattered sites in the Prairie Pothole Region or that may often destroy duck nests in a few localities in the region include the following. Cats (Felis catus) and dogs (Canis familiaris) occur at rural residences throughout the region but seldom eat duck eggs (Stoddard 1932, Darrow 1938, Riggert 1977, Figley and VanDruff 1982). Thirteen-lined ground squirrels (Spermophilus tridecemlineatus) occur throughout the region (Hall 1981) and eat bird eggs (Lein 1968, Creighton 1971, Graul 1972). However, they seldom depredate duck nests because of the large size and thick shell of the eggs (Errington 1938, Sowls 1948, Sargeant et al. 1987). Norway rats (Rattus norvegicus) eat duck eggs (Anderson 1957) and are widely distributed throughout the region (Jones et al. 1983). However, they live primarily in refuse sites near human habitation (Jones et al. 1983), where few ducks nest. The northern harrier (Circus cyaneus), a common raptor throughout the region (Sargeant et al. 1993), occasionally preys on pipping duck eggs (Willms and Kreil 1984). The gray wolf (Canis lupus), gray fox (Urocyon cinereoargenteus), black bear (Ursus americanus), spotted skunk (Spilogale putorius), and river otter (Lutra canadensis) have potential to destroy many duck nests but occur in few localities in the region (Stoddard 1932, Darrow 1938, Banfield 1974, Hall 1981, Jones et al. 1983, Sargeant et al. 1993). The common raven (Corvus corax), a noted depredator of duck nests (Einarsen 1956, Jarvis and Harris 1971, Stiehl and Trautwein 1991), occurs only in scattered sites, mostly along the northern edge of the region (Sargeant et al. 1993). The bulIsnake (Pituophis melanoleucus), another depredator of duck nests (Imler 1945, Glup and McDaniel 1988), occurs only in scattered sites in the southeastern portion of the region (Conant 1958).
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