The Collaborative International Dictionary of English v.0.48:

Yaup \Yaup\, v. i. [See Yap, and Yelp.]
   To cry out like a child; to yelp. [Scot. & Colloq. U. S.]
   [Written also yawp.]
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Yaup \Yaup\, n. [Written also yawp.]
   [1913 Webster]
   1. A cry of distress, rage, or the like, as the cry of a
      sickly bird, or of a child in pain. [Scot. & Colloq. U.
      S.]
      [1913 Webster]

   2. (Zool.) The blue titmouse. [Prov. Eng.]
      [1913 Webster]

WordNet (r) 3.0 (2006):

yaup
    v 1: emit long loud cries; "wail in self-pity"; "howl with
         sorrow" [syn: howl, ululate, wail, roar, yawl,
         yaup]