Common Grackle    Quiscalus quiscula

Migratory Status: Short-distance migrant

PIF Population Estimate: 97 000 000

Percent of western hemisphere population breeding in boreal forest: <25%

BAM Effective Detection Radius (m) : 84.93

PIF Maximum Detection Distance (m) : 200

Canadian BBS Population trend: -0.2 n.s. (-1.0 to 0.5)

Life History

Gregarious, loud, opportunistic, and a nuisance are just some of the adjectives and terms that have been used to describe the Common Grackle. More common in the eastern United States and Canada, this highly adaptable flocking species often congregates in winter flocks of excess of one million birds and sometimes targets agricultural crops, giving it a negative reputation.

In North America, the Common Grackle’s breeding range extends from Newfoundland in the east, southward along the Atlantic coast to Florida and the Gulf Coast. In the south, its range continues westward into New Mexico and Texas, and in the north, westward into eastern British Columbia. Throughout its range, the Common Grackle has been highly successful and has adapted to any semi-open and open habitats that have scattered trees and shrubs. They can be found breeding in swamps, marshes, open woodlots, old agricultural fields, urban gardens, cemeteries, and conifer plantations.

During the non-breeding season, the Common Grackle lives, migrates, and forages in large mixed species flocks, often in close proximity to woodlots and agricultural fields. Its winter range extends from parts of southern Ontario in Canada, to Minnesota and New England in the United States, southward along the Atlantic coast to Florida and the Gulf Coast, and west into Texas and New Mexico.

The Common Grackle, like many other blackbirds, has predominately dark plumage with an iridescent sheen to it. Three subspecies exist in North America; the ‘Bronzed’ Grackle (Q. q. versicolor) is the most common and has the largest range. Males of this subspecies have a bronzed body and a black head, neck, breast and tail that is glossed purple. The ‘Florida’ Grackle (Q. q. quiscula), found in the extreme southeast, is distinguished by its green back and blue-green tail, while the ‘Purple’ Grackle (Q. q. stonei), which occurs east of the Appalachians and southern New England, has a purplish body with a green-blue glossy tail. In all populations, adults have yellow eyes, long tails, and long bills. The song of the Common Grackle is harsh and has been described as a rusty gate or, phonetically, as “readle-eak”.

Common Grackles are omnivores and part of their success and adaptability to new environments is their unrestricted diet. They are opportunistic feeders and will scavenge on garbage, steal from other birds, as well as take advantage of abundant food sources, such as agricultural crops. Common Grackles generally forage on the ground for insects, seeds, nuts, and other invertebrates, but will also wade into shallow water for fish and aquatic invertebrates, as well as forage in trees and shrub.

Reference(s)

Peer, B. D., and E. K. Bollinger. 1997. Common Grackle (Quiscalus quiscula), The Birds of North America Online, . A. Poole, Ed. Ithaca: Cornell Laboratory of Ornithology; Retrieved from The Birds of North America Online database: http://bna.birds.cornell.edu/bna/species/271