Geology topics
Research about Manitoba
Source-linked reports with geographic coverage including Manitoba.
Waterfowl breeding habitat in agricultural and nonagricultural land in Manitoba
Waterfowl populations and habitat characteristics were examined on 33 potholes in each of two 16-square-mile study areas of agricultural and nonagricultural land in southwestern Manitoba. The agricultural land potholes, lacking in or incompletely surrounded by trees, received greater use by lesser scaup ( Aythya affinis ), canvasback ( A. valisineria ), redhead ( A. americana ), coot ( Fulica americana ), and three species of grebes ( Podicipedidae ). The nonagricultural land potholes, completely surrounded by trees, were more attractive to blue-winged teal ( Anas discors ), and mallard ( A. platyrhynchos ), and over twice as many dabbler broods were censused there. Abundant, undisturbed nesting cover may have been the reason for greater dabbler use on the nonagricultural land potholes since chemical and biological properties suggest more fertile conditions in the agricultural land.
Selective feeding by juvenile diving ducks in summer
Waterfowl often fail to use foods that seem plentiful to the investigator. The extent to which selective feeding or rejection of foods is a function of behavioral and morphological adaptations of the species, conditioned behavior of the individual, or individual preference for certain foods has not been appraised. The objectives of our study were to determine: (1) the extent of selective feeding among juvenile Canvasbacks ( Aytha valisineria ) and redheads ( A. americana ), (2) which food items were and which were not utilized, and (3) how selective use was related to the relative quality and availability of the food resource. In another paper (Bartonek and Hickey, MS) we present findings on the food habits of juvenile and adult Canvasbacks, Redheads, and Lesser Scaup ( Aytha affinis ) in southwestern Manitoba primarily during late spring and summer. Only a few of the limited number of investigations into the summer food habits of waterfowl correlate use of foods with the relative quantity and/or availability of potential foods (White, 1936; Beard, 1953; Keith, 1961; Chura, 1961; Perret, 1962; Collias and Collias, 1963). Perret (1962) concluded that seasonal variations in the food habits of Mallards ( Anas platyrhynchos ) were related to changes in the availability of foods.