​ JACK DAW, or DAW, in ornithology, Colæus or Corvus monedula, the smallest of crows, being but 13 inches in length. The general color is black, with a grayish shade on the margins of the feathers, the back and wings purplish; the crown of the head is glossy blue-black, forming a cap; the neck hoary-gray, the bill and feet black, the eye bluish-white.