Spring diets of sympatric Greater Snow Geese and Canada Geese in southern Quebec

• Published in: Canadian Journal of Zoology
• Main Authors: Giroux, Jean-François, Bergeron, Renée
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1996
• Subjects: Branta canadensis
• Online Access: http://dx.doi.org/10.1139/z96-107; http://www.nrcresearchpress.com/doi/pdf/10.1139/z96-107

We compared the diets of Greater Snow Geese (Anser caerulescens atlantica) and Canada Geese (Branta canadensis) during their spring staging period at Lake St. Pierre in southern Quebec. In waste cornfields, diet was established by examining the esophageal contents of birds shot while feeding, whereas in grasslands, diet was determined by microhistological analysis of plant fragments found in droppings. Corn accounted for >95% of the diet of both species when feeding in cornfields. Grasses, especially Phleum pratense, dominated the diet of both species in all grassland habitats (>86%), whereas legumes represented <5%. The relative proportions of some food items differed between the species but constituted only a small portion of the overall diet. The high degree of similarity in the diets of these two species when feeding in the same habitats suggests that there is little ecological segregation and, thus, potential for competition. Feeding by geese in cornfields has no impact on the subsequent crop yield. Although grazing can decrease harvestable biomass, this is presently unlikely in the Lake St. Pierre area because of the pattern of habitat use by geese.