cheep

Short definition from Wiktionary

Verb

1. 1
   Of a small bird, to make short, high-pitched sounds.
2. 2
   To express in a chirping tone.

Noun

1. 1
   A short, high-pitched sound made by a small bird.
2. 2
   A similar-sounding short high-pitched sound

Interjection

1. 1
   The short, high-pitched sound made by a small bird.