
You’ll often find Common Grackles in large flocks, flying or foraging on lawns and in agricultural fields. They strut on their long legs, pecking for food rather than scratching. At feeders Common Grackles dominate smaller birds. When resting they sit atop trees or on telephone lines, keeping up a raucous chattering.
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. Since my yard has an abundance of Oak trees, we have quite the feast for these noisy birds.
I found this fact to be quite interesting. 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. What a wonder of creation!
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. This explains why there are so many of them this time of year.
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 when nesting in the spring. No wonder large groups of Grackles are referred to as plagues!