Introduction

The Common Grackle is a large and conspicuous blackbird (subfamily Icterinae) of eastern North America that frequents open areas with scattered trees. Its yellow eyes, iridescent bronze or purple plumage, and long, keel-shaped tail give it a striking appearance. It is semicolonial, preferring coniferous trees, and is one of the first species to begin nesting in the spring, often by late March or early April in the central portion of its range.

The Common Grackle is extremely flexible in both feeding and nesting behavior. The clearing of eastern forests in the 1700–1800s, in association with agricultural activity, has increased suitable nesting habitat for it and provided additional food sources. Within the past fifty years, it has invaded the West, aided by increased planting of shelterbelts. As a result, this species is now one of the most successful and widespread in North America.

The rapid increase in population size has had some negative consequences. The Common Grackle is now among the most significant agricultural pest species in North America, causing millions of dollars in damage to sprouting corn. It has also earned a reputation for eating other birds’ eggs and nestlings, and it occasionally kills and consumes adult birds. Control measures may now be contributing to the decline of its numbers in the East.