The Blue Jay (Cyanocitta cristata) is one of North America’s most recognizable and intelligent birds, known for its bright blue plumage and varied vocalizations. These highly opportunistic foragers have a diverse diet that adapts to seasonal availability and local food sources. Seeds and nuts form a substantial, calorically dense portion of their diet, especially during colder months when other food is scarce. This adaptability allows them to thrive in various environments, from deep forests to suburban backyards.
Specific Feeder Seeds
Blue Jays readily visit backyard feeders, preferring high-fat, easily accessible options. Black oil sunflower seeds are their favorite, prized for their thin shells and high fat content, which provides concentrated energy. Their strong bills can easily crack the thin shell of the black oil variety, making them preferable to the larger, thicker-shelled striped sunflower seeds.
Once a seed is cracked, the bird often holds the food item against a perch with its foot to consume the kernel. While they eat safflower seeds, their enthusiasm is lower compared to sunflower seeds and peanuts. Safflower seeds have a tough shell that can deter less determined birds, but Blue Jays are capable of cracking them open when preferred foods are scarce.
They typically ignore small, low-value seeds like millet, often flicking them out of feeders in search of better morsels. Blue Jays quickly grab multiple seeds, sometimes stuffing over a hundred sunflower kernels into their expandable throat pouch (gular pouch). They then fly off to hide them, ensuring a reliable food source later.
Natural Nuts and Acorns
In their natural environment, acorns are an important food source, often constituting a majority of their diet in winter. Blue Jays are adept at selecting viable acorns, sometimes showing an 88% accuracy rate in choosing nuts likely to germinate. They use their robust beaks to hammer open the hard shells, often bracing the nut against a branch for leverage.
The caching of acorns is a well-documented behavior, and Blue Jays play a significant ecological role as primary dispersers of oak trees. A single jay can hide several thousand acorns in a season, burying them individually up to three kilometers away from the source tree. They also enjoy other large tree nuts:
- Pecans
- Walnuts
- Beechnuts
- Hickory nuts
At backyard feeders, peanuts are extremely popular, whether offered in the shell or shelled. Peanuts, although technically legumes, provide high levels of protein and unsaturated fat, serving the same nutritional purpose as nuts. The birds often shake peanuts in the shell to judge their weight and quality before caching them.
Other Essential Foods
While seeds and nuts are a staple, Blue Jays are true omnivores; vegetable matter accounts for up to 75% of their diet over the year. During warmer months, especially the breeding season, their diet shifts to include more protein-rich animal matter. This includes a variety of insects such as caterpillars, grasshoppers, and beetles, which they forage for in trees and on the ground.
They also consume fruits and berries from shrubs and trees, providing necessary moisture and carbohydrates. Blue Jays occasionally eat small vertebrates like frogs or mice, and are known to consume carrion. They are sometimes observed raiding the nests of other birds for eggs and nestlings, though research suggests this behavior is a rare occurrence in their overall diet.