Blue Jay — 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.
The Blue Jay measures about 30 cm from bill to tail and weighs 70–100 g (2.47-3.53 ounces), with a wingspan of 34–43 cm (13–17 in). 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. Males and females are nearly identical; males are slightly larger. There is 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 may be fully raised. When frightened, the crest bristles outwards, brush like. When the bird is feeding among other jays or resting, the crest is flattened to the head.
As with other blue-hued birds, the Blue Jay’s coloration is not derived by pigments, but is the result of light refraction due to the internal structure of the feathers; if a blue feather is crushed, the blue disappears as the structure is destroyed. This is referred to as structural coloration.
The Blue Jay is generally assertive toward other birds, and it may 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 has also been known to sound an alarm call when hawks or other dangers are near, often helping the plight of smaller birds. 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.
The Blue Jay has been known to be a raider of other bird’s nests, stealing eggs, chicks, and nests. However, this may not be as widespread as is typically thought. Cornell’s website describes a study that found only 1% of Blue Jay’s had evidence of nestlings or eggs in their stomachs. It appropriates American Robin nests. Young jays collect brightly coloured or reflective objects, such as bottle caps or pieces of aluminum foil, and carry them for a moment.
Blue Jays in captivity have been observed using strips of newspaper as tools to obtain food.