Common grackles (Quiscalus quiscula) are self-assured birds that walk proudly with their heads held high. When seen close up in the sunlight, their black feathers shimmer with iridescent blues, purples, and browns reminiscent of peacock feathers. Their eyes are yellow.
Birds of a feather flock together, and grackles like to hang out with other blackbirds that look a lot and act a lot like themselves. Solitary grackles rarely remain so, charitably inviting all of their similarly-colored relatives, including cousins up to the nth degree, as well as red-winged blackbirds and starlings. Together they form great clouds of blackbirds that forage for food in the winter and during spring and fall migrations.
Just as people who live in Evansville flock to the supermarket and clear out the shelves at the first hint of a snowflake in the air, grackles flock to backyard feeders and clear them out when it starts to snow. Other birds---cardinals and sparrows, titmice and chickadees, finches and wrens---are excluded from the blackbird club and are likely to find nothing left once the blackbirds have flown away.
Common grackles are generally monogamous, breeding between March and July, and usually raise only one brood per year. The female builds the nest that will hold four or five blue/ gray eggs. It takes about two weeks for the eggs to hatch and another two weeks until the chicks are ready to leave the nest. Only half of the chicks live to be adults. The oldest recorded age for a grackle is 22 years and 11 months.
Grackles, though social, occasionally get into fights with other grackles or even kill and eat other birds, especially house sparrows. Grackles eat insects and other arthropods, such as spiders. They also will eat frogs, salamanders, mice, minnows, crayfish, worms, small bats, and fruit. During the winter and during migration, they prefer grain from corn fields and will also eat acorns.
Predators of grackles include people (large numbers of grackles are killed to protect crops), fox squirrels and gray squirrels, snakes, cats, raccoons, and red-tailed hawks.
Grackles prefer open areas with scattered trees, terrain that is common in southwestern Indiana. Although their affinity for corn makes them a bane for farmers, grackles are also beneficial for agriculture because they consume large quantities of insects, such as Japanese beetles and cutworms, that damage crops.
Grackles are protected under the Federal Migratory Bird Treaty Act as native migratory birds. The act provides an often-used exception, however, if grackles threaten agricultural crops, livestock, trees, wildlife, or pose a public nuisance.
Less drastic means can be used to reduce grackle populations at bird feeders.
- When grackles first appear at the feeder, avoid placing birdseed out for a few days, if possible, until the flock moves on.
- Use feeders that have wire screening or small perches that allow only small birds to reach the seed. Unfortunately, any feeder that will accommodate a cardinal is likely to allow grackles.
- Set out birdseed at a time of day when grackles do not usually forage. Cardinals, sparrows, doves, and juncos, for example, will eat late in the afternoon/ evening after grackles have already left to roost.
- Move the feeder from an open area to an area closer to trees and shrubs, but be careful of making it more attractive to squirrels.
According to the National Audubon Society, the common grackle is among the top twenty of common North American birds that have experienced the greatest decline in population in the last four decades. Populations of these common birds have declined by an average of 68 percent, and all of the birds on the top-twenty list have lost at least half of their populations between 1967 and 2007. Many common birds in Great Britain are also in decline.
Although there are still millions of grackles lining the utility wires and blanketing the fields, the large decline in population of grackles and other common birds should not be dismissed as inconsequential. Birds can be harbingers of harmful changes in the environment that affect the survival not only of birds but other species, including humans.
For more information about the common grackle, see the following websites:
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