If there were to be a contest to throw one bird species off the planet, the common grackle would likely be a nominee. The grackle has a reputation as an avian thug. "The bully of the bird world," it is sometimes called. Even the serious literature promotes this image. Princeton University's "New World Blackbirds" ascribes to it "a raptor-like expression." In his "ID GUIDE" Richard Crossley says the grackle has a "bad boy look."
To be sure, the grackle rap sheet is a long one. This is an aggressive bird that tends to take over, dominating approaches to backyard feeders, for example, and sometimes excluding other birds all together. This irritates a birder seeking a good look at a migrant sparrow, for example, or even a goldfinch. The grackle raids the nests of other birds and it gathers in large flocks and leaves a mess behind. All of these offenses are committed by a bird that could be called an invader.
None of the charges make the grackle any less handsome or less interesting, and on cross examination, the charges appear less serious than the bird's reputation suggests.
The grackle certainly is an opportunist. Grackles eat almost anything, but careful study of what's left of a grackle meal - yes scientists study this - shows that vertebrates, including birds, make up less than 1 percent of the grackle-far, far less than that of such widely admired species as the peregrine falcon, which is pretty nearly exclusively a bird eater. The same is true for Cooper's hawks. Insects are the major item in the grackle diet. They are clever birds, though. Scavenging grackles have been seen taking stale bread, which they place in water to soften it up before eating it. Like gulls, they sometimes follow farm equipment, taking mice and worms. Perhaps resourceful would be the proper adjective to describe these behaviors. Another word that might apply is "rapacious." Grackles can become pests, taking more grain or corn than growers like, especially in the southern states, where huge flocks of grackles gather to spend the winter months.
Changes in the environment have made it possible for grackles to expand their range, and in the last half century, they've overspread the Great Plains. Two factors were especially important in this conquest. One was an expanding food supply made available by human activities, including farming, as we've seen, but mostly also discarding items that the grackles scavenge and consume. The other was trees. The Plains had few of these before humans began building towns and planting shelterbelts. Grackles depend on trees for nesting cover and for communal roosts. A treeless landscape is a landscape without grackles. Grackles like the new plains landscape, with substantial stands of trees interrupted by farm fields, and today they are found across the continent as far west as the Rocky Mountains and as far north as the tree line.
These grackle offenses alone might its reputation, but it is the bird's apparent arrogance that really puts people off. Grackles strut about, lording it over backyards and intimidating every creature that uses them, cats and dogs and kids included. One might wonder what the grackle is so proud of - but that would be committing the crime of anthropomorphism, which is attributing human traits to non-human species, a temptation better left avoided.
It is a fact, though, that the grackle is a good-looking bird - though not at first sight. At first sight, the overall impression is of a good-sized, blackish bird. Let the sun strike the feathers, however, and all is changed. The splendor of its iridescence is the grackle's redemption in a birder's eyes.
Most grackles display a purple sheen around the head and shoulders, and this led to the earlier common name for the species, purple grackle. On other parts of the body, in other light and from other angles, the grackle shows off other colors, often including green and bronze. Purple is too limiting a description. Common is more fitting; the grackle is a common bird. In 1990, Bird Life International estimated the North American population at 90 million birds, and it probably hasn't shrunk since then.
Grackles have one more notable physical attribute, a keel-like tail. The grackle is able to raise the outer feathers of its tail, and often does, apparently in courtship and in dominance displays, but also because it can, I have concluded after a week watching grackles closely.
I admit that I lured them by spreading sunflower seeds on my driveway, then settling back in a deck chair to watch the show. The grackles did not disappoint, but I'll cut the food supply now that I've seen the show.