Bird Profile

Common Grackle

A grackle flock can empty a hopper feeder in a morning, and it is fully protected by federal law. Everything you can legally do about it comes down to making the feeder awkward to use.

The Common Grackle (Quiscalus quiscula) is a long-tailed, yellow-eyed blackbird about a foot (30 cm) long that arrives in flocks, feeds on the ground and on any flat surface, and can strip a hopper feeder between breakfast and lunch. It is native to North America and fully protected by the Migratory Bird Treaty Act, which means every legitimate response is about the feeder, not the bird.

The good news is that grackle exclusion is genuinely easy compared with squirrel-proofing. Grackles are big, heavy and clumsy on small perches, and they dislike safflower. Two changes solve most of the problem.

This profile covers how to identify grackles and separate them from the other black birds they flock with, the seasonal pattern behind the flocks, the feeder geometry that shuts them out, and why a bird that feels overwhelming in your yard is in serious continental decline.

How to identify a Common Grackle#

Size and shape do most of the work. A grackle is noticeably larger than a starling or a Red-winged Blackbird, with long legs, a heavy pointed bill and a tail that is long, wedge-shaped and often folded into a V-shaped keel in flight, as if the bird were dragging a rudder.

The eye is the clincher: a pale staring yellow eye in an all-dark head. At any distance where you can see eye color, you have your answer.

Plumage is glossy black at a glance and iridescent up close. Birds in the Northeast and Midwest tend toward a bronze-toned body with a blue-purple head; birds along the Atlantic coastal plain and in the Southeast show more purple and green iridescence across the body. Females are smaller, less glossy and shorter-tailed than males.

Sorting the black birds#

In the South, check for Boat-tailed Grackle near the coast and Great-tailed Grackle in Texas and the Southwest. Both are considerably larger with absurdly long tails, and the females are brown rather than black.

When grackles take over, and for how long#

The flocks are seasonal. Grackles that breed in the northern part of the range migrate, moving south in loose blackbird flocks in fall and pushing north again from late winter through early spring. The result at a feeder is a wave: a yard that had two grackles in January has forty in March.

That wave usually passes in one to three weeks. Through the breeding season you are more likely to see a handful of local pairs, and in fall large flocks form again for the trip south, often mixed with starlings, Red-winged Blackbirds and cowbirds. Feeding through those windows is covered in feeding birds during migration.

What grackles eat#

Grackles are broad omnivores. Roughly speaking, insects and other animal food dominate in summer and grain and seed dominate in winter, but they will take almost anything: beetles, grubs, caterpillars, spiders, small fish, crayfish, frogs, mice, fruit, acorns, waste grain, and the eggs or nestlings of other birds on occasion.

They have a hard keel on the roof of the mouth that lets them saw open acorns, which is unusual for a songbird and part of why they are so hard to starve out of a yard.

At feeders they concentrate on the same easy, high-calorie items starlings do.

Feeder tactics that actually exclude grackles#

In rough order of how much difference they make for the effort:

1. Take off the trays and shorten the perches. A tube feeder with perches under three quarters of an inch (2 cm) and no bottom tray is close to grackle-proof. A tray converts the same feeder into a grackle platform.
2. Switch to safflower. Full switch, not a blend. Give your regular birds a couple of weeks to adjust.
3. Cage everything you can. A caged feeder with mesh around 1.5 inches (4 cm) admits chickadees, titmice, nuthatches and finches, and stops grackles cold.
4. Use weight-activated feeders. The same mechanism sold for squirrels closes under a grackle. Details in squirrel-proof feeders.
5. Retire the platform for the duration of the wave. An open platform feeder cannot be made grackle-resistant. Put it away in March and bring it back in May.
6. Clean up the ground. Grackles feed heavily on spill, and a swept patio removes the anchor that keeps a flock coming back.

The complete tactical sequence, including what to do when a flock refuses to leave, is in grackles and blackbirds taking over.

Behavior worth knowing#

Grackles walk rather than hop, striding across lawns with the head held forward. In spring, males perform a bill-up display, pointing the bill vertically at a rival, and puff and stiffen their feathers into an angular posture while making a sound often compared to a rusty gate.

They practice anting, deliberately picking up ants and rubbing them through the feathers, apparently using the formic acid against parasites. They also bathe eagerly and will use a bird bath in numbers.

Roosting is the behavior that surprises people most. Outside the breeding season grackles gather in communal roosts that can hold tens of thousands of birds and, mixed with starlings, blackbirds and cowbirds, occasionally reach the millions. Those roosts empty into the surrounding countryside each morning, which is why a rural feeder can go from empty to overwhelmed in five minutes.

Nesting#

Grackles are loosely colonial, often putting several nests in the same stand of conifers, and they favor dense evergreens near water. The nest is a bulky cup of grass and mud placed in a spruce, pine, cedar or shrub, usually 3 to 30 feet (1 to 9 m) up.

Clutches run 4 to 5 eggs, pale blue-gray with dark scrawls. Incubation is about 12 to 14 days and young leave the nest roughly two weeks after hatching. Females do the incubating; males often desert as the season progresses.

A colony near your yard is the usual reason grackles persist through summer rather than passing through. Planting a more layered yard with native plants does not deter them, but it does support the insect populations that pull them away from your feeder.

Population and status#

Grackles remain numerous enough that they feel unstoppable in a spring flock. Continental survey data tells a different story: long-running counts show Common Grackle numbers falling steeply since the 1960s, on the order of half the population or more, which has put a bird almost nobody thinks of as vulnerable onto lists of common species in steep decline.

The causes are not settled. Changes in agriculture, reduced waste grain, and control programs aimed at winter roosts have all been proposed. The reasonable conclusion for a backyard is that the flock in your yard is a local surplus, not a sign of a species doing well.

A setup that survives grackle season#

• One caged sunflower feeder, mesh about 1.5 inches (4 cm).
• One nyjer feeder, which grackles ignore entirely.
• Hopper switched to safflower for the spring, no cracked corn anywhere.
• Trays off, perches short, platform stored until May.
• Ground swept twice a week, which also reduces rodents and moldy seed.
• Bird bath kept running, since grackles use it but so does every other bird and the water is worth more to your yard than the seed they take.