Régime alimentaire d'oiseaux fréquentant un agrosystème

Abstract

The gizzard content analysis of red-winged blackbirds, common grackles, cowbirds, starlings, and pigeons allowed us to evaluate the volume of corn and barley ingested by these birds. Our results indicate that all these birds eat invertebrates, except for the pigeon, which consumes only grain. The starling does not eat corn and consumes very little barley. The common grackle has a corn diet of 45.2%, while the red-winged blackbird, the pigeon, and the cowbird consume 23.3%, 17.6%, and 5.7% respectively. Barley also occupies an important place in the diet of these four bird species: 49.9% for the pigeon, 28.3% for the cowbird, 17.4% for the red-winged blackbird, and 14.5% for the common grackle. Oats were noticed in a few common grackle and pigeon gizzards. The volumes of all other species of seeds found in the gizzards were not as great as that of corn and barley. Insects are prevalent, especially Coleoptera, which account for 53.5% of the starlings' diet, 21.0% of the red-winged blackbirds' diet, 18.2% of the cowbirds' diet, and 17.0% of the common grackles' diet.