Why are they called Blue "Jays"?

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Blue Jay Cyanocitta cristata
Order: PASSERIFORMES Family: Crows and Jays (Corvidae)

Description
Blue jays are bright blue birds with blue head crests, black wing markings and black necklaces. They are a large songbird about 10-12 inches and weigh about 3 ounces

Behavior

Bright and bold, blue jays often travel in noisy family groups in late summer and fall. Their discovery of good feeding sight is announced to the whole community of birds. They also are very good at giving early warnings of hawk, cats, or other predators in the area.

General
Their name “Jay” has its origins from the Latin “gaius” meaning “gay or merry.” The species name cristata originates from the Latin word crista, meaning “crested.” The longevity record for banded Blue Jays in the wild is over 17 years, the longest of any of the jays.