What is "ornitho-"

Ornitho- \Ornitho-\ [Cf. Ern.] A combining form fr. Gr. 'o`rnis, 'o`rniqos, a bird.

before vowels ornith-, word-forming element meaning "bird, birds," from comb. form of Greek ornis (genitive ornithos) "a bird" (in Attic generally "domestic fowl"), often added to the specific name of the type of bird, from PIE *or- "large bird" (see erne).

pre. of or pertaining to birds