The common grackle is a common and often urban blackbird of eastern North America. Polytypic. Length 12.6".
A large blackbird with strong legs and a long, graduated tail that is held in a deep keeled shape during the breeding season. Adult male: entirely black with noticeable iridescence in good light. Widespread form shows bronze gloss to body, blue head, and purple or blue iridescence on wings and tail. The iridescence of the head is different from that of the body, and changes abruptly; this applies to all forms of common grackle. Eyes are bright yellow, while legs and bill are black. Adult female: smaller and duller than male and does not hold tail in deep keel shape. Juvenile: brown, with dark eyes and faintly streaked on breast.
Three subspecies. The bronzed grackle (versicolor), found northwest of the Appalachians, has bronze iridescence on body, a blue head, and purplish tail and wings. The purple grackle (stonei), found southeast of the Appalachians, has a purplish body and head, with a blue or greenish glossed tail. The Florida grackle (quiscula), ranging from Florida to southern Louisiana and South Carolina, has a greenish iridescence on its back.
Brewer’s and rusty blackbirds lack the long, graduated tail of common grackle, and they never hold it in a keeled shape. Boat-tailed and great-tailed grackles are much larger, with even more striking tails. Common grackles show a clear, abrupt division between the gloss color of the head and body.
Call: a loud and deep chuck. Song: a mechanical, squeaky readle-eak. Both sexes sing.
Status and Distribution
Abundant. Year-round: open and edge habitats, urban areas, agricultural lands, golf courses, swamps, and marshes. Migration: diurnal migrant; southern populations resident. Arrive at breeding areas mid-February–mid-March and early April in northernmost sites. Begins southward movements as early as late August, peaking October–early November. Vagrant: casual to far north, Alaska, Yukon, Northwest Territories, and Churchill, Manitoba. Also casual in Pacific states and British Columbia.
Populations have boomed due to human alteration of habitat and spilled grain, but in the last 30 years the numbers have decreased significantly in the East. In the Northwest, populations and range are increasing.
—From the National Geographic book Complete Birds of North America, 2006