The common grackle – the “bird we love to hate.” Photo by John Hess

Evanston news delivered free to your inbox! 

The common grackle is “the bird we love to hate.”

In human portrayals, it is self-confident; a raucous invader; an uncanny thief; cocky; a hooligan; sassy; exceptionally intelligent; a very smart bird with an intimidating gaze; more than just a common nuisance.

“The grackles, I don’t even want to think about them” is a common curse.  

Common grackles are native to the Americas east of the Rockies, from Canada to Key West to Texas. Before European settlement, they were probably uncommon, nesting in groves of cottonwood and sycamores along watercourses. Clearing the eastern forests for agriculture, cities and towns in the 1700s and 1800s created the perfect grackle habitat: open areas with scattered stands of trees, particularly evergreens.
The population of these adaptable, omnivorous birds soared.

Grackles are sleek black birds, about the length of a mourning dove. They have a long black bill, long black legs, and a long, keel-shaped tail. Though the casual observer might think it a crow, the grackle is smaller and not even in the same family. Field guides distinguish between two forms, the bronzed grackles of the Midwest, and the purple grackles of the southeast. Most striking on the bronzed grackle is the adult’s iridescent coloring on its head and shoulders, a mixture of bluish-blackish green, violet, olive, and bronze, and its brilliant yellow eyes. Females tend to be a little shorter and less iridescent. The purple grackle’s feathers are purple and green gloss all over. By any measure, both are handsome birds.

Common grackles are members of the Icteridae family, songbirds found only in the Americas. The family includes orioles, bobolinks, meadowlarks and cowbirds as well as other blackbirds. They are commonly known as the songbirds that cannot sing, their high-pitched “song” most frequently reminiscent of a rusty hinge.

Grackles are decried by farmers for devouring grain and by bird-lovers for devouring bird seed and chasing away favored species from feeders.

John J. Audubon’s print, called “The Purple Grackle or Common Crow-Blackbird,” depicts a pair perched on a corn stalk busy at their “nefarious propensities,” a corn kernel in the mouth of one, and the cobs partially stripped. Further on, he exonerates them for eating the grubs that would have destroyed the corn seedlings.

Although corn seems to be their favorite food, they will eat any fruit or seed crop in season, including sunflowers, rice and peanuts. If an object is too hard, such as a  peanut or stale bread, they will repeatedly dip it into water until it is soft enough to eat. Their diet also includes insects humans consider pests (they eat Japanese beetles) and an occasional small bird. One farmer’s negative mindset was changed, at least temporarily, after his entire corn crop was wiped out by grasshoppers. Amazed, he watched as a flock of grackles appear out of nowhere and devour every last grasshopper.

They also enjoy acorns. They score the outside of the acorn and then saw it open with a sharp keel inside their mouths. One Central Park blogger (http://10000 spent a lunch hour tossing acorns up in the air to a group of grackles, thereby getting close-up photos of their beautiful plumage. A reader commented that the iridescence “reminded him of mother of pearl in so many mollusk shells.” ( http://10000birds).

Male grackles may arrive on their breeding grounds in late winter even earlier than their cousins, the red winged  blackbirds. Females arrive a week later. They seek out groves of conifers near water for nesting.
Wilmette’s Gillson Park offers an ideal habitat, and they nest in the red pines north of the harbor. They may nest in colonies of 100 or more, but 10-20 is more typical. Their small territory may be defended only a foot or so from their nest.

Courtship begins with a chase, one female in the lead and a pack of males following. The female and her chosen mate engage in courtship displays that involve vocalizations, bill pointing, tail “ruffing-out” accompanied by peeps and squeaks. They are usually monogamous.

Females choose the nest site and build a well-camouflaged nest, a large bulky cup-like straggly affair, made of woody stems, leaves and fine grasses accessorized with paper, string, fishing line, cloth, feathers, tape, wire, etc. and lined with mud. Males are attentive during nest-building and throughout egg laying, but, during incubation, they are likely to stray.

A clutch averages five eggs of varying colors. If predators interfere, the female may lay another clutch. She incubates the eggs for an average of 13 days, and both sexes participate in feeding the nestlings, who remain in the nest another 13 days.  During the breeding season, the young are fed primarily animal food.  After fledging, the young remain near the nest for a couple of days. Adults feed them for several weeks, after which the young and adults join roosting flocks, sometime in late July. Most adults return to their breeding sites in following years.

Grackles are social animals, frequently found in groups, although they can be solitary. Their day is spent foraging for food at feeders, picnic areas, and agricultural fields, and roosting at night near agricultural fields and orchards and along tree-lined city streets. Roosts may be noisy and messy.

Birds considered an agricultural nuisance may be killed despite the Migratory Bird Treaty Act, and grackles have been the target of lethal and non-lethal controls.  The eastern population has decreased by about 30 percent over the past 50 years, although the cause is unknown, while the species is expanding westward. 

Some grackles overwinter in this area, but most will soon begin their migration toward the Gulf of Mexico in huge flocks along with red-winged blackbirds, cowbirds and starlings.  If a mob of grackles descends into a yard, patience is the only response. They will quickly be on their way south.

Libby Hill

Libby Hill is the author of "The Chicago River: a Natural and Unnatural History. She has been writing about birds and trees and Evanston's natural history for the Roundtable since 2004.