Bluebirds, encompassing the Eastern, Western, and Mountain species, are songbirds whose diet shifts dramatically with the changing seasons. While they are primarily known for their insect-foraging habits, their ability to adapt their menu allows them to survive the colder months. Understanding this varied dietary need is important for anyone seeking to attract and support these beautiful creatures throughout the year. The transition from a summer diet high in protein to a winter diet rich in carbohydrates is a key element of their survival.
The Primary Bluebird Diet
During the spring and summer breeding seasons, the bluebird’s diet is heavily weighted toward invertebrates, which provide the high protein necessary for raising their young. Studies indicate that insects and other arthropods account for approximately 68% of an adult bluebird’s food intake over the course of a year. The bulk of this protein comes from soft-bodied prey like caterpillars, grasshoppers, crickets, and beetles.
Bluebirds are visually oriented foragers, often utilizing a “perch-and-pounce” strategy to spot and capture their prey on or near the ground. They will sit on an elevated branch or wire, scan the open area below, and then swoop down to seize an insect. This method is effective for finding the ground-dwelling arthropods that sustain them when they are most active. This intense focus on insects persists until the late autumn when the ground freezes and prey populations dwindle.
Essential Berries and Native Fruits
As the weather cools and insect availability decreases, bluebirds naturally turn to fruits and berries, which can make up as much as 50% of their diet during the winter. These fruits serve as a high-energy source, offering the fats and carbohydrates necessary for maintaining body temperature and surviving cold snaps. The most beneficial fruits are those native varieties that persist on the branch long after the leaves have fallen.
Native plants like flowering dogwood, American holly, and Eastern red cedar provide berries that become a dietary mainstay for wintering flocks. The berries of staghorn and smooth sumac are also consumed, as are those of Virginia creeper and wild grape, which offer high caloric density. Bluebirds, like many other frugivorous birds, can safely eat the berries of certain plants that are toxic to humans, such as poison ivy and pokeweed.
These native options are superior to cultivated fruits because they have evolved to provide the specific nutritional profile—namely, a balance of fats and sugars—that birds require for winter survival. For instance, dogwood berries are often swallowed whole, with the bluebird later regurgitating the large pit once the fleshy part has been digested. This reliance on persistent, native fruit ensures they have a reliable food source when other options are covered by snow or ice.
Providing Fruit Throughout the Year
Making fruit available to bluebirds involves careful landscaping and supplemental feeding during times of scarcity. Planting native trees and shrubs that bear fruit in the late fall and winter is the most sustainable way to support their natural feeding behavior. Species such as juniper, sumac, and the various native hollies should be prioritized as they retain their berries through the harshest months.
For supplemental feeding, particularly during periods of heavy snow or deep cold, a variety of store-bought fruits can be offered in open tray feeders. Chopped apples, pears, blueberries, and raspberries are readily accepted. Dried fruits such as raisins and currants are also popular, but they should be softened by soaking them in water beforehand to make them easier to digest. Placing these offerings near a protective shrub line helps the birds feel secure while they feed.