Measurements
Both Sexes
- Length
- 11–13.4 in
28–34 cm - Wingspan
- 14.2–18.1 in
36–46 cm - Weight
- 2.6–5 oz
74–142 g
Relative Size
- Larger than a Red-winged Blackbird; about the same size as a Mourning Dove
Other Names
- Quiscale bronzé (French)
- Zanate norteño (Spanish)
Cool Facts
- Those raggedy figures out in cornfields may be called scare-crows, but grackles are the #1 threat to corn. They eat ripening corn as well as corn sprouts, and their habit of foraging in big flocks means they have a multimillion dollar impact. Some people have tried to reduce their effects by spraying a foul-tasting chemical on corn sprouts or by culling grackles at their roosts.
- Common Grackles are resourceful foragers. They sometimes follow plows to catch invertebrates and mice, wade into water to catch small fish, pick leeches off the legs of turtles, steal worms from American Robins, raid nests, and kill and eat adult birds.
- Grackles have a hard keel on the inside of the upper mandible that they use for sawing open acorns. Typically they score the outside of the narrow end, then bite the acorn open.
- You might see a Common Grackle hunched over on the ground, wings spread, letting ants crawl over its body and feathers. This is called anting, and grackles are frequent practitioners among the many bird species that do it. The ants secrete formic acid, the chemical in their stings, and this may rid the bird of parasites. In addition to ants, grackles have been seen using walnut juice, lemons and limes, marigold blossoms, chokecherries, and mothballs in a similar fashion.
- In winter, Common Grackles forage and roost in large communal flocks with several different species of blackbird. Sometimes these flocks can number in the millions of individuals.
- Rarely, Common Grackles nest in places other than their usual treetops, including birdhouses, old woodpecker holes, barns, and in still-occupied nests of Osprey and Great Blue Heron.
- The oldest recorded Common Grackle was 22 years 11 months old.
Habitat
Open Woodland
Common Grackles do well in human landscapes, using scattered trees for nesting and open ground for foraging. Typical natural habitats include open woodland, forest edge, grassland, meadows, swamps, marshes, and palmetto hammocks. They are also very common near agricultural fields and feedlots, suburbs, city parks, cemeteries, pine plantations, and hedgerows. Unbroken tracts of forest are the only places where you are unlikely to find Common Grackles.
Food
Omnivore
Common Grackles eat mostly seeds, particularly agricultural grains such as corn and rice. Other seeds include sunflower seeds, acorns, tree seeds such as sweetgum, wild and cultivated fruits, and garbage. In summer, one-quarter or more of a grackle’s diet may be animals, including beetles, grasshoppers, caterpillars, spiders, crustaceans, mollusks, fish, frogs, salamanders, mice, and other birds.
Nesting
Nesting Facts
- Clutch Size
- 1–7 eggs
- Number of Broods
- 1-2 broods
- Egg Length
- 1–1.3 in
2.5–3.3 cm - Egg Width
- 0.7–0.9 in
1.9–2.3 cm - Incubation Period
- 11–15 days
- Nestling Period
- 10–17 days
- Egg Description
- Light blue, pearl gray, white, or dark brown, usually spotted with brown.
- Condition at Hatching
- Blind and naked except for sparse brownish down; poorly coordinated, weighing just under a quarter-ounce.
Nest Description
Females typically build the nest, with males sometimes helping or making repairs. The nest can take as little as a week to as long as six weeks to finish. It’s a bulky cup made of twig, leaves, and grasses along with bits of paper, string, cloth, corn husks and other incidental materials. The female reinforces the nest cup with mud and then lines it with fine grasses and horse hair. The finished nest is 6-9 inches across, with an inside diameter of 3-5 inches and a depth of 3-9 inches.
Nest Placement
Tree
The female chooses the nest site, with the male sometimes following along as she surveys. After beginning to build, females often seem to change their minds and select another site. Typically the nest is high in a coniferous tree between two vertical limbs or on a horizontal branch (although they’ve been recorded as low as 8 inches off the ground and in deciduous vegetation, cattails and other sites). Nests are often built near water. Rarely, Common Grackles nest in unusual places such as birdhouses, woodpecker holes, cliff crevices, barns, and still-occupied nests of Osprey and Great Blue Herons.
Behavior
Ground Forager
Common Grackles are large, noisy, and gregarious birds that often flock with other blackbirds, cowbirds, and starlings, especially in winter. At feeders they tower over other birds and push them aside to get at food. Grackles typically forage on the ground and roost high in trees or on power lines. Common Grackles sometimes nest in loose colonies of up to 200 pairs, showing little territoriality except in the immediate area of the nest. In spring when birds are pairing, you may see three kinds of playful chases: first, a group of males will fly after a slow-flying female; second, a single male will chase a female at high speed; and third, a male and female will fly slowly and conspicuously alongside each other. In normal flight, grackles fly in a direct path on stiff wingbeats.
Conservation
Least Concern
Common Grackles are abundant and widespread. They have grown in numbers and extended their range westward, following the spread of agriculture. Their tendency to form large flocks has them suspected of causing immense damage to crops, and this has made them the target of eradication campaigns, though their numbers remain strong.
Credits
- Dunne, P. 2006. Pete Dunne’s essential field guide companion. Houghton Mifflin, Boston.
- Ehrlich, P. R., D. S. Dobkin, and D. Wheye. 1988. The birder’s handbook. Simon & Schuster Inc., New York.
- Patuxent Wildlife Research Center Longevity Records: http://www.pwrc.usgs.gov/bBL/homepage/long4930.htm
- Peer, Brian D. and Eric K. Bollinger. 1997. Common Grackle (Quiscalus quiscula), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/271
Migration
Resident or short-distance migrant. Grackles from the far-northern U.S., Canada, and the Great Plains winter in the central and southern U.S.
Backyard Tips
During migration, set up bird feeders in your yard with a variety of mixed grain and seeds. Spreading grain or seed on the ground helps, as this is where Common Grackles prefer to feed – and if they come to the ground they may let smaller birds continue to use the feeders. Bear in mind that too much grain scattered on the ground can attract rodents, so it's best to sprinkle just as much as the birds are likely to eat at any one time.
Find This Bird
Common Grackles are familiar inhabitants of wet, open woodland and marshes as well as in suburbs, parks, and agricultural fields. A good way to find them is to scan large flocks of blackbirds and starlings. The tallest, longest-tailed blackbirds you see will most likely be Common Grackles.
Get Involved
Keep track of the Common Grackles at your feeder with Project FeederWatch
Look for Common Grackle nests and contribute valuable data about them through NestWatch
Report your Common Grackle sightings to eBird
Learn more about bird photography in our Building Skills section. Then contribute your images to the Birdshare flickr site, which helps supply the Cornell Lab of Ornithology's websites with photos, including All About Birds.
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Common Grackle from Bent's Life Histories of North American Birds (1958)
Explore sounds and video of Common Grackles from the Cornell Lab of Ornithology's Macaulay Library archive