The Blue Jay (Cyanocitta cristata) is a passerine bird and member of the crow family Corvidae native to North America. It is adaptable, aggressive and omnivorous.

Distribution and habitat
The Blue Jay is generally aggressive toward other birds, and it will chase birds from feeders or other food sources. It may chase birds of prey, such as hawks and owls, which occasionally prey on jays, and will scream if it sees a predator within its territory. 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 attacks it until it takes a new roost. The Blue jay is a slow flier and an easy prey for hawks and owls, when it flies in open lands. It flies with body and tail held level, with slow wing beats.

Behavior
The voice is typical of most jays in being varied, but the most commonly recognized 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. Blue Jays will use these calls to band together to drive a predator such as a hawk away from their nest.
Blue Jays also have quiet, almost subliminal calls which they use among themselves in proximity. One of the most distinctive calls of this type is often referred to as the "rusty pump" owing to its squeaky resemblance to the sound of an old hand-operated water pump. In fact, they can make a large variety of sounds, and individuals may vary perceptibly in their calling style. Like other corvids, blue jays may learn to mimic human speech. [1]

Diet
The breeding season begins in mid-March, peaks in mid-April to May, and extends into July. Any suitable tree or large bush may be used for nesting, though an evergreen is preferred, and the nest is built at a height of 3 to 10 m.The adults build a cup-shaped nest of twigs, small roots, bark strips, moss, other plant material, cloth, paper, and feathers, with occasional mud added to the cup.