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Webster 1913 Edition

Noun.

An animal that yelps, or makes a yelping noise.

Specifically:

(Zool.)

(a)

The avocet; – so called from its sharp, shrill cry.

[Prov. Eng.]

(b)

The tattler.

[Local, U. S.]

yelper ‎(plural yelpers)

One who yelps.
- 2009 July 21, Nate Chinen, “Vocals That Deliver a Jolt, as ‘Ooh’ Morphs Into ‘Eh’”, in New York Times:
  Mr. Longstreth, who can be a bit of a yelper, sang sweetly, perhaps in search of contrast.
(Britain, dialect) The avocet (so-called from its sharp, shrill cry).
(US, dialect) A bird, the tattler.