The helminths in the digestive tract of the mallard and pintail in southern Manitoba
Crichton, Vincent F. J.
This study was designed to identify the parasites of the mallard and pintail in southern Manitoba and to examine the role of these parasites in the regulation of the host populations. The Delta marsh was the centre of the study during 1967- 1968. One hundred and one mallards and 100 pintails were examined for helminths. The average helminth burden in the mallards was 243 per bird and 189 in the pintails. Mallards harboured an average difference of 56 helminths per bird more than pintails. The following kinds of helminths were recovered: Cestoda, five genera containing five species; Trematoda, seven genera with seven species; Nematoda, six genera with seven species; and Acanthocephala, two genera with two species. Both birds are host to a similar helminthfauna but the mallards have a greater intensity of infection than pintails. Similar foods were found in the crops of both species. The mallard may be more susceptible to parasitism than the pintail. The helminths in the host duck caused neither emaciation of the breast muscles nor a weight loss. The effects of the parasites in times of stress could be greater on mallards than pintails. The parasite fauna of the canvasback was similar to that of mallards and pintails but the numbers were greater in the former. The helminthfauna variability is just as great within each of these host species as between the two closely related hosts.