The Eastern, Western, and Mountain Bluebirds are highly sought-after visitors, known for their striking plumage and cheerful calls. Attracting these members of the thrush family requires more than a standard seed mix. Unlike many common backyard birds, bluebirds have distinct dietary needs reflecting their evolutionary history. Understanding their primary food sources and providing high-protein supplements is the most effective way to support them through the breeding season and the colder months.
The Truth About Seeds
Bluebirds are classified as “soft-billed” birds, meaning their beaks are not designed for cracking hard shells like those of finches or grosbeaks. They possess short, slender beaks better suited for grasping soft-bodied prey. This physical adaptation is why bluebirds generally do not consume common birdseed, such as sunflower seeds, millet, or cracked corn.
These birds are primarily insectivores, and their digestive systems are optimized to process the protein found in invertebrates. While a bluebird might occasionally investigate a seed mix, it is usually looking for dried fruit pieces or insect larvae. If they do consume seeds, it is typically soft, hulled options like sunflower chips or nut meats, which act as a supplement rather than a staple food.
Primary Natural Food Sources
The bluebird’s natural diet shifts dramatically with the seasons, driven by the availability of protein-rich arthropods. During the spring and summer breeding season, up to 80% of an adult bluebird’s diet consists of insects and other invertebrates. They actively hunt for ground-dwelling prey such as caterpillars, grasshoppers, crickets, beetles, and spiders.
Bluebirds often employ a “perch-and-pounce” strategy, scanning the ground from an elevated position before swooping down to capture their meal. This hunting method ensures they maximize the high-protein intake necessary for raising their young. Nestlings rely almost exclusively on soft-bodied insects for rapid growth.
As the weather cools and insect populations decline in the fall and winter, the bluebird diet transitions to soft fruits and berries. They seek out native plants that retain their fruit through the winter months, providing a source of carbohydrates and energy when insects are scarce. Preferred natural winter foods include the berries from dogwood, sumac, wild grape, and Virginia creeper. These soft, fleshy fruits offer sustenance until the spring warmth returns.
Optimal Feeder Offerings
To successfully attract bluebirds, feeder offerings must directly mimic the high-protein insect diet they rely on. The single most effective food supplement for bluebirds is the mealworm, the larval stage of the darkling beetle. Mealworms, whether live or freeze-dried, provide a concentrated source of protein that supplements their natural diet.
Mealworms
Offering mealworms in a specialized bluebird feeder or a shallow, open dish helps ensure the intended recipient gets the treat. Bluebirds quickly recognize the shape of the mealworms. Some specialized feeders feature small entrance holes that deter larger birds, giving bluebirds exclusive access. If using freeze-dried mealworms, soaking them in warm water for a few minutes can increase their appeal and make them easier to consume.
Suet
Another suitable offering is soft suet, particularly crumbly, peanut butter, or fruit-infused varieties, rather than hard beef-fat plugs. Suet provides much-needed fat and calories, making it an excellent winter food source when the birds need extra energy to maintain their body temperature. Avoid suet that contains large, hard seeds, opting instead for mixes with small bits of fruit or nuts.
Fruit
Small, soft fruit pieces can also be offered to supplement their winter diet. Bluebirds will readily take items like raisins, currants, or chopped apple pieces placed on an open platform feeder. When offering raisins, cutting them in half and soaking them in water can improve their digestibility and appeal.