Peewee

Noun

 * 1)  A short or small person; a small object.
 * 2) 🇺🇸 A player in a sports league for very young children.
 * Is five too young for peewee football?

Noun

 * 1)  A magpie-lark or mudlark, Grallina cyanoleuca
 * 2) A Pewee.

Thesaurus
Lilliputian, Tom Thumb, bairn, bantam, banty, bitsy, bitty, brownie, button, cherub, child, chit, darling, diminutive, dwarf, dwarfish, elf, featherweight, fine, fingerling, gnome, homunculus, innocent, itsy-bitsy, kid, kitten, lamb, lambkin, lightweight, lilliputian, little bugger, little fellow, little guy, little innocent, little one, little tad, little tot, manikin, midge, midget, mini, miniature, minikin, minnow, minny, minute, mite, mouse, nipper, nubbin, offspring, pip-squeak, pony, pygmy, runt, shaver, shrimp, slip, small fry, snip, snippet, tad, teeny, teeny-weeny, tiny, tit, tot, wart, wee, wee tot, wisp

Etymology 1
Probably reduplication of wee:

Etymology 2
Probably onomatopoeia from the birds' songs.