University of Maryland Extension



Blackbirds are a common term for a variety of birds that are similar in appearance and behavior. In Maryland, common "blackbirds" include Grackles, Cowbirds, and Red-winged blackbirds. Starlings, although not considered a true blackbird will also be considered here. Their similar behavioral traits include an omnivorous diet, generally feeding in very large flocks, roosting at night in very large groups, and mass migrations.

All species can become problems when their massive flocks, in the thousands, swarm in a field of crops and destroy it, or invade both home and commercial orchards. In home gardens, blackbirds will sometimes pull up seedlings as they emerge. Their night roosting (rookery) in trees or on buildings by the hundreds or even thousands is another serious nuisance because of their droppings. This is usually more common during the fall and winter. There are possible health problems associated with the excessive buildup of droppings around a roost site.

If blackbirds are a problem, home gardeners can use lightweight netting to keep them away from high-value crops. Individual ears of sweet corn can be protected by placing paper bags over them after the silk has turned brown. Frightening devices such as scarecrows work for a very short period of time. Moving the frightening devices around frequently makes them more effective. To disperse a blackbird roost, the landowner should harass the birds every time they begin to congregate. The key to successfully dispersing a roost is persistence and using many different types of harassment, such as loud noises, lights, water, etc.

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