Lewis Short
ornīthĭas (noun M) = ὀρνιθίας:
* The bird-wind, a wind that blows in spring and brings with it the birds of passage: Favonium quidam a. d. VIII. Cal. Mart. Chelidoniam vocant, ab hirundinis visu: nonnulli vero Ornithian, uno et sexagesimo die post brumam, ab adventu avium, flantem per dies novem,Plin. 2, 47, 47, § 122; Vitr. 1, 6; App. Mund. p. 62; Col. 11, 2, 21.—The Etesiae are also sometimes called Ornithiae, Plin. 2, 47, 47, § 127.
Charlton T. Lewis, Charles Short, A Latin Dictionary