Put a cage or screen around your seed feeders so only smaller birds can get to the food. Build your own using chicken wire or buy one of the commercial bird feeders made especially to solve this problem.
Use a Hopper type feeder with a weighted perch that closes when a heavy bird lands on it.
Keep bird seed off the ground and stop filling your platform feeder for a week. Blackbirds may get discouraged and move on.
Shorten the perches on your tube feeders. The smaller birds (Goldfinches, Chickadees and Titmice) will be able to eat but larger birds will not be able to land.
Never buy seed mixes containing milo. Blackbirds are the only birds that seem to like milo! Blackbirds also like millet and cracked corn, but few of the colorful songbirds eat these seeds. You might try offering safflower seeds instead of sunflower seeds in your tube feeders.
