Why is the ninth month called September?
1877, "small, tiny, for children," a dialect word, possibly a varied reduplication of wee. Attested earlier (1848) as a noun meaning "a small marble." (Baseball Hall-of-Famer Harold "Peewee" Reese got his nickname because he was a marbles champion before he became a Dodgers shortstop.) As a type of bird (variously applied on different continents) it is attested from 1886, imitative of a bird cry.
A short or small person, animal, etc: That peewee doesn't scare me (1877+)
any of eight species of birds of the genus Contopus (family Tyrannidae); it is named for its call, which is monotonously repeated from an open perch. In North America a sad, clear "pee-oo-wee" announces the presence of the eastern wood pewee (C. virens), while a blurry "peeurrr" is the call of the western wood pewee (C. sordidulus). Some authorities consider the western form to be a race of C. virens. Both forms are plain birds, about 14 cm (6 inches) long, that resemble the eastern phoebe; the two forms differ from the eastern phoebe, however, in being browner and more slender and in having two distinct whitish wing bars