The Blue Jay is a mainly blue bird with a white chest, a blue crest, and a black collar around its neck. The Blue Jay’s blue colour is not due to pigmentation like other coloured birds, but due to light interference with the internal structure of the feathers. If the feather is crushed the blue colour will disappear.
Blue Jays will eat nuts, seeds, fruit, songbird eggs and even small vertebrates from trees and they have been known to hide nuts to eat later like squirrels. Blue Jays are very fond of acorns and because of this are thought to have helped with the spread of oak trees after the last glacial period.
They are a very noisy and aggressive bird but are very slow fliers which makes them prey to hawks and owls. Having a Blue Jay around can be very beneficial to other birds as it has been known to make an alarm call when a predator is in the area and other birds recognize this call and hide.
Blue Jays are very intelligent birds and like to grab brightly coloured or reflective objects and carry them around until they lose interest. Blue Jays can make numerous calls and can even mimic hawk calls to see if there is a hawk in the area or to scare other birds away from a food source. The Blue Jay even has a call that gathers all of the Blue Jays in the area together to mob a predator like a hawk.
Blue Jays are monogamous, which means they may go a life-time with one mate. Both the male and the female help build the nest and the male feeds the female while she lays on the eggs. Blue Jays also take part in a fascinating act called anting. During anting, birds will pick up ants in their beaks and rub them on their wings and tail feathers. While it is not completely understood why birds undergo this behaviour, one theory is that it is related to comfort or feather maintenance as it occurs when the birds undergo molting and the secretions from the ants soothe the skin. Another theory is that it controls parasites like lice and mites that live in the birds feathers.
– V. Nolan (2014)