The common grackle, Quiscalus quiscula, is a large blackbird native to North America that can quickly become a nuisance at backyard feeding stations. These birds measure between 11 and 13 inches in length and often arrive in large, noisy flocks, especially during the spring migration period. Their size and gregarious behavior allow them to dominate feeders, aggressively chasing away smaller songbirds like finches and chickadees. Grackles have a voracious appetite and can empty a full feeder of seed in minutes, requiring a multi-faceted approach to reclaim the feeding station for smaller species.
Adjusting Feeder Mechanics for Exclusion
Physical exclusion is an effective method for deterring large birds like grackles by manipulating the feeder’s design to make it unusable for their size and weight. Weight-activated feeders use a calibrated spring mechanism to detect the weight of a landing bird. When a heavier bird lands on the perch, the feeding port automatically closes off access to the seed supply. The mechanism can often be adjusted, allowing lighter songbirds to feed without triggering the closure.
Caged feeders provide a permanent physical barrier around the seed reservoir, allowing access only to birds small enough to pass through the wire mesh. The optimal mesh spacing for exclusion is approximately 1.5 inches by 1.5 inches. This size is large enough for small birds like chickadees and nuthatches, yet too restrictive for the grackle’s broader body and wingspan. Select a model where the seed ports are positioned several inches inside the wire cage, preventing grackles from reaching the food with their long bills.
Feeders with short or unstable perches exploit the grackle’s need for a secure landing spot when feeding. These larger birds require a stable, horizontal perch to balance their body weight while eating, and they are generally unable to hover like smaller finches. Shortening the existing perches on tube feeders to less than one inch, or removing them entirely, forces the birds to cling or hover. Perches trimmed to a small size are typically too unstable to support a grackle.
Strategic Food Choices to Discourage Grackles
Manipulating the menu makes the feeding station less attractive to grackles. These omnivorous birds are particularly drawn to inexpensive seed mixes that contain filler ingredients. Eliminating these preferred items is the first step in discouraging a persistent flock. Switching the main offering to foods that are difficult to access or have a less palatable taste can significantly reduce grackle visits.
Filler Ingredients
- Cracked corn
- Millet
- Milo
- Hulled sunflower seeds
Safflower seed is one of the best alternatives; many smaller songbirds enjoy it, but grackles find it unappealing. The seed has a slightly bitter flavor generally disliked by grackles and starlings. Furthermore, the thick, hard shell of the safflower seed is difficult for them to crack open, making the effort-to-reward ratio too low. Nyjer seed is another deterrent due to its small size. The grackle’s large, heavy bill is poorly suited for efficiently extracting the tiny Nyjer seeds from specialized finch feeders, encouraging them to seek an easier meal elsewhere.
Grackles also readily consume suet, but this can be managed by altering the presentation and composition of the fat cakes. Using an upside-down suet feeder forces birds to hang upside down to access the food, a maneuver easily performed by woodpeckers and nuthatches, but difficult for the less acrobatic grackle. Suet cakes mixed with capsaicin are effective because they protect the suet from competition with mammals like squirrels, ensuring more food remains for the smaller target birds.
Environmental Deterrents and Feeder Location
The placement of the feeding station is a strategy for managing grackle activity. Grackles prefer to congregate and stage their approach from perches in dense trees or on utility wires near the feeder. Moving the feeder away from these staging areas can make them feel less secure and less inclined to dominate the feeding area. Feeder poles should be installed a minimum of eight feet away from any structure the birds can use as a launch point.
Installing wide, slick baffles is a physical modification that prevents large birds and climbing mammals from accessing the feeder. For pole-mounted feeders, a cone-shaped or cylindrical baffle should be installed off the ground. The smooth, slick surface prevents grackles from gaining a foothold and climbing the pole to the seed reservoir. A dome-style baffle placed above a hanging feeder can also deter them from landing directly on top of the feeding mechanism.
Simple visual deterrents use light and movement to create an environment that feels unpredictable and threatening to the grackles. Hanging reflective flash tape or iridescent Mylar film strips near the feeder uses wind-driven movement to produce a disruptive, flickering effect. While these objects provide an immediate deterrent, grackles are intelligent and can quickly become habituated to a stationary object. To maintain effectiveness, these reflective items should be repositioned frequently to preserve the illusion of a new and unsettling threat.