Bird seed types: which seeds attract which birds and what to skip

Black-oil sunflower seed has a higher fat content and thinner shell than striped sunflower. The thin shell means smaller birds (chickadees, house finches) can crack it, while larger birds (cardinals, blue jays) prefer it over other seeds anyway. The high fat content provides more energy per seed than millet or milo.

Cornell Lab's Project FeederWatch data consistently shows black-oil sunflower seed attracts the largest number of species and the highest total bird visits of any single seed.

Nyjer seed (marketed as thistle, but botanically Guizotia abyssinica) is the primary food source for American goldfinches at feeders. Its small size requires a feeder with narrow ports to prevent spillage; standard sunflower feeders waste nyjer through the gaps.

Nyjer seed is sterilized before sale per USDA requirement, so it does not germinate under the feeder. It is oil-rich and provides high energy. Store in a cool, dry location: nyjer can go rancid if stored in heat, and finches will reject stale seed.

Safflower seed has a bitter coating that squirrels, European starlings and grackles dislike. Cardinals, mourning doves and house finches eat it readily. Switching to safflower in a yard with heavy squirrel pressure reduces feeder depredation without requiring a squirrel-proof feeder mechanism.

Birds that have not encountered safflower before sometimes take a few days to accept it. If birds seem to ignore the safflower initially, mix it 50/50 with black-oil sunflower seed and decrease the sunflower portion over 2 weeks as birds adapt.

White proso millet is the preferred seed for ground-feeding sparrows and juncos. It is a small, round seed with a mild flavor that also attracts doves. Present millet in a low platform feeder or directly on the ground in a dry area under a sheltering shrub.

Red millet and golden millet are common filler seeds in cheap mixes but are eaten reluctantly by most birds. When buying a seed blend, check the ingredient list: the presence of red millet, milo (sorghum) or wheat in large quantities indicates a filler-heavy mix that birds will sort through and reject.