Blue Jays. Probably a bird you know pretty well, or think you know. common to the backyard bird feeders of north america, these distinctively colored birds are often overlooked, and have a few hidden, shall we say, feathers, that you might not be aware of. 

Native to the forested northern United States, this largely vegetarian bird lives on a diet of seeds, nuts, acorns, and a variety of bugs including beetles, caterpillars, and grasshoppers. A blue jay is much like a squirrel, in the way that both bury their acorns in the ground to store them for long periods of time. When an acorn is forgotten, it aids the growth of the forest. On occasion, they have been known to eat eggs or nestlings of other birds, but this is rather uncommon. 

the blue jay's “Jay! Jay!" song is quite a familiar sound, it is the call most identify with this bird, but as it turns out, this bird is capable of making many different calls, and frequently mimics hawks, especially the red-shouldered variety. as well as bird calls, clear whistled notes and gurgling sounds can often be heard. 

The Blue Jay has a crest on top of it's head, this crest changes its position with the birds' emotions. an upright crest is a sign of aggression, while a brush-like crest symbolizes fear and a flattened crest is seen in a relaxed calm bird. It's colorful plumage of bright blues, grays and white, is present in both the female and male birds, as well as the chicks. 

Often these birds are seen pushing smaller species off the bird feeder, with loud obnoxious calls, and an aggressive attitude, however the blue jay is also well versed in the realm of stealth, silently tending to it's nest and chicks, as to not bring the attention of a predator. their nests are most often built in the v's between branch and tree trunk, made of grass, small twigs, bark, paper and sometimes held together with a "glue" made of mud.

Fairly social and typically found in pairs, family groups or small flocks, the Blue Jays  Migration patterns are irregular and hard to follow, one individual might migrate one year, and not the next. According to a National Geographic article, It is unclear what factors determine whether each blue jay or blue jay family decides to migrate. 

References: 
National Geographic Website
The Cornell Lab, All About Birds, website
Audubon Guide To North American Birds, website