Blue Jay

The Blue Jay (Cyanocitta cristata) is a passerine bird in the family Corvidae, native to eastern North America. It lives in most of the eastern and central United States. It breeds in forests, and is common in residential areas. Its coloration is predominantly blue, with a white chest and underparts, and a blue crest; it has a black, U-shaped collar around its neck and a black border behind the crest. 
The blue jay feeds mainly on seeds and nuts, such as acorns, which it may hide to eat later; soft fruits; arthropods; and occasionally small vertebrates. It gleans food from trees, shrubs, and the ground, and sometimes hawks insects from the air. Blue jays can be very aggressive to other birds; they sometimes raid nests and have decapitated other birds
It builds an open cup nest in the branches of a tree. The clutch may be two to seven eggs, which are blueish or light brown with darker brown spots. Young are altricial, and are brooded by the female for 8–12 days after hatching. They may stay with their parents for one to two months.
Description
The Blue Jay a pronounced crest on the head, a crown of feathers, which may be raised or lowered according to the bird's mood. When excited or aggressive, the crest will be fully raised. When frightened, the crest bristles outwards, brushlike. When the bird is feeding among other jays or resting, the crest is flattened on the head. Its plumage is lavender-blue to mid-blue in the crest, back, wings, and tail, and its face is white. The underside is off-white and the neck is collared with black which extends to the sides of the head. The wing primaries and tail are strongly barred with black, sky-blue, and white. The bill, legs, and eyes are all black
Behavior
The blue jay is a noisy, bold, and aggressive passerine. It is a moderately slow flier. It flies with body and tail held level, with slow wing beats. Its slow flying speeds make this species easy prey for hawks and owls when it flies in open areas. Predators may prey on jay eggs and young up to their fledgling stage, including Squirrels, Snakes, Cats, Crows, Raccoons, Opossums, other jays and possibly many of the same birds of prey who attack adults.
The blue jay can be beneficial to other bird species, as it may chase predatory birds, such as Hawks and Owls, and will scream if it sees a predator within its territory. It has also been known to sound an alarm call when hawks or other dangers are near, and smaller birds often recognize this call and hide themselves away. It may occasionally impersonate the calls of raptors, especially those of the red-tailed hawks, possibly to test if a hawk is in the vicinity, though also possibly to scare off other birds that may compete for food sources. It may also be aggressive towards humans who come close to its nest, and if an owl roosts near the nest during the daytime the blue jay mobs it until it takes a new roost. However, blue jays have also been known to attack or kill other smaller birds, and bat species such as Eastern red bats. Jays are very territorial birds, and they will chase others from a feeder for an easier meal. Additionally, the blue jay may raid other birds' nests, stealing eggs, chicks, and nests.
Diet
Blue jays are omnivorous. They have strong black bills which they use for cracking nuts, usually while holding them with their feet, and for eating corn, grains and seeds. Blue jays love to eat peanuts in the shell.  Its food is sought both on the ground and in trees and includes all known types of plant and animal sources, such as acorns and beech mast, weed seeds, grain, fruits and other berries, peanuts, bread, meat, small invertebrates of many types, scraps in town parks, bird-table food and eggs and nestlings. Blue jays will sometimes cache food, though to what extent differs widely among individuals. Although seemingly contentious in their general behavior, blue jays are frequently subservient to other medium-sized birds who visit bird-feeders. In Florida, blue jays were dominated at feeders by eastern gray squirrels, Florida scrub-jays, common grackles and red-headed woodpeckers, all of which were occasionally observed to aggressively prevent the jays from feeding.
Vocalizations
Blue jays can make a large variety of sounds, and individuals in their calling style. Like other corvids, they may learn to mimic human speech. Blue jays can also copy the cries of local hawks so well that it is sometimes difficult to tell which it is. Their voice is typical of most jays in being varied, but the most commonly sound is the alarm call, which is a loud, almost gull-like scream. There is also a high-pitched jayer-jayer call that increases in speed as the bird becomes more agitated. This particular call can be easily confused with the chickadee's song because of the slow-starting chick-ah-dee-ee. Blue jays will use these calls to band together to mob potential predators such as hawks and drive them away from the jays' nests.
In Human Culture
The blue jay was adopted as the team symbol of the Toronto Blue Jays Major League Baseball team, as well as some of their minor league affiliates. Their mascot, Ace, is a blue jay. The blue jay is also the official mascot for Johns Hopkins University, Elmhurst University, and Creighton University. The latter two spell the name as one word - Bluejay. A notable example from fiction includes Mordecai from the American animated series, Regular Show.