The common grackle is a medium-sized blackbird. Its plumage is black, and it has a sheen which is glossy and iridescent. Generally, the head, neck and breast are glossy purplish-blue or bluish-green. However, there is distinctive regional variation in coloring--in the New England area and in the West, the subspecies shows brassy bronze colorations from behind, east of the Alleghenies the reflection is purple, and yet another difference is shown in the southeast where the coloration is of a greenish hue. The female is smaller and duller than the male. The bills of both sexes are long, sharp and black. The average length of the common grackle is 28-34 cm. The tail is long (longer in males than in females) and keel-shaped. The adults' eyes are yellow. Juveniles have brown plumage and brown eyes. (Terres, 1980; Peer and Bollinger, 1997)1

A common grackle is primarily a forager and lives off any type of fruit, seed, nut or other plant matter it can find. Most common grackles are monogamous and form pairs in early spring. The female chooses the nesting site and the male usually begins to help the female by collecting items for the nest. The male follows the female very closely, effectively stabilizing the pair bond and to disallow extra-pair bonding. Nests typically consist of 5-6 eggs and half of all males leave the nest after the eggs are hatched. The common grackle's nests are parasitized by cowbirds though grackles actively defends it's nests from such birds. The common grackle is migratory except is areas such as the Gulf Coast states, where weather changes are so drastic.

Though it is highly gregarious, a grackle may attack other grackles as well as other species of birds. Attacks on other birds may involve biting, pecking, scratching, and flying toward the enemy. The common grackle eats other birds' eggs and nestlings, and even occasionally kills and eats other adults birds, especially the adult house sparrow. It is territorial only around the the nest site. The pair actively defends the nest by mobbing, chasing or diving at predators, including humans.

The common grackle is considered to be the most populous bird in the United States and may easily be observed migrating in large flocks.


1Terres, J. The Audubon Society Encyclopedia of North American Birds. Alfred A Knopf, New York, 1980

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