Though this feels like a modern invention, Jay has been in use for centuries. Early Jays often were named in honor of founding father John Jay, whose surname derived from the jaybird. A popular mid-century choice, Jay was in the Top 100 from 1956 to 1970. In the last couple of decades he was replaced by such more elaborate forms as Jayden, Jaylen, and Jayce. But Jay could make a comeback in tandem with cousins May, Kay, Fay, and Ray. Now at Number 394 in the US, Jay is ranked Number 80 in Scotland, 102 in Northern Ireland.
In literature, the most prominent Jay wasn't a Jay at all—Gatsby's birth name was James Gatz. In real life, the honor goes to Jay Leno, also born James.
In India, Jay is used as a modern variant of the Hindi Jaya, which means "victory."