The Common Grackle (Quiscalus quiscula) is an abundant and gregarious blackbird found in partly open situations with scattered trees, open coniferous and deciduous woodlands, forest edges, and suburbs. It breeds across approximately the eastern two thirds of Canada (from Alberta to southern Quebec) and the United States (from Montana, Colorado and easten New Mexico to the Atlantic and Gulf Coasts), with the winter range contracting to the southeast of the much broader breeding range. The range has been expanding westward in recent decades. Two forms (both appearing all black at a distance) were at one time recognized as distinct species: The "Bronzed Grackle", which occurs in most of New England and west of the Appalachians, has a bronze back, blue head, and purple tail; the smaller "Purple Grackle", found east of the Appalachians, has a narrow bill, purple head, bottle green back, and purple tail. Birds from the mid-Atlantic states show variable head color and a purplish back with iridescent bands of variable color. The familiar song of the Common Grackle resembles the sound of a creaking gate; the call note is a loud, deep chuck.

Common Grackles are omnivorous . They forage mainly by walking on the ground or wading in very shallow water. Outside the breeding season, they usually forage in flocks.

Common Grackles often nest in small colonies of 10 to 30 pairs (sometimes as many as 100 or more) and several males may perch in adjacent treetops to sing their creaking, grating songs. In courtship, the male fluffs out his body feathers, partly spreads his wings and tail, and delivers a short scraping song; he also postures with his bill pointing straight up. The nest is typically built in dense vegetation less than 6 m above the ground. The nest, which is built by the female, is a bulky open cup of weeds, grass, and twigs, usually with some mud added, and the inside is lined with fine grass. The 4 to 5 (sometimes as few as two or as many as 6) pale blue eggs are blotched with brown. Incubation is by the female only for 12 to 14 days. Both parents feed the young, bringing them mostly insects. The young leave the nest around 16 to 20 days after hatching.

Common Grackles are present year-round across much of their range. Migration usually involves large flocks. In the north, migration takes place quite early in spring and rather late in the fall.

(Kaufman 1996; AOU 1998; Dunn and Alderfer 2011)