They like robin nests and often appropriate them for nesting. The bird is omnivorous, meaning they eat everything, but about 75 percent of their diet is vegetable matter. This choice of diet is seasonal, as blue jays prefer insects, salamanders, tree frogs and even mice during warm weather. Their love of acorns should make tree lovers happy, because blue jays commonly bury acorns and never retrieve them. This makes the blue jay a kind of avian Johnny Appleseed, and it is probable that, along with squirrels, the blue jay helped reforest North America as the glacier retreated about 12,000 years ago.
Blue jays are aggressive, curious and large when compared to most of the other perching birds.
Their cousins the ravens are the largest of the perching birds. If you've ever had a pair of jays nest near your house, you may have been attacked and pecked if you came too close to their nest. Young jays commonly collect brightly colored objects like bottle caps and pieces of aluminum foil and carry them about for awhile. Sometimes they try to peck open such objects, or they will use them as platforms and simply sit atop them until they get bored with the new-found curio. As noisy and aggressive as they can be, blue jays are very secretive during the nesting season.