DYNAMICS OF PARASITIC INFECTIONS AT 4 SITES WITHIN LESSER SNOW-GEESE (CHEN-CAERULESCENS-CAERULESCENS) FROM THE BREEDING COLONY AT LA-PEROUSE BAY, MANITOBA, CANADA

We enumerated parasite burdens within the blood, gizzard, ceca, and ki dneys of adult female lesser snow geese Chen caerulescens caerulescens collected from the breeding colony at La Perouse Bay, Manitoba, Canad a, in 1989. We observed 5 species of nematodes, 1 species of digenean, 1 species of protozoan, and an unidentified microfilaria in these gee se. We compared parasite burdens between geese collected during the in cubation (2-14 June) and brood-rearing (1-5 August) periods. There was a significant decrease in the prevalence and intensity of the gizzard nematode Amidostomum spatulatum and a significant increase in the pre valence of the renal coccidium Eimeria truncata between the 2 collecti on periods. We suggest that the changes concerning A. spatulatum refle ct transmission conditions some 6 months earlier when the geese were o n the wintering grounds. Changes involving E. truncata reflected trans mission conditions within the previous month. Consequently, it would a ppear that breeding colonies are the foci for transmission of E. trunc ata, a significant pathogen of adults and goslings.