Brewer's: Gallus Numidicus
(A). A turkey cock. Our common turkey comes neither from Turkey nor Numidia, but from North America.
“And bedecked in borrowed plumage, he struts over his pages as solemnly as any old Gallus Numidicus over the farmyard.” —Fra. Ollie (1885)
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894