peewee

Etymology 1

Probably reduplication of wee (“small”).

noun

1. (informal) A short or small person; a small object.
2. A kind of small marble in children's games.
   You separate the marbles by color until you have four groups, but then you notice that some of the marbles are regulars, some are shooters, and some are peewees. 2011, Jamie MacLennan, ZhaoHui Tang, Bogdan Crivat, Data Mining with Microsoft SQL Server 2008
3. (US, sports) A player in a sports league for very young children.
   Is five too young for peewee football?
   1971 November, Pat Strange, Mini Judoka in Aussie Ladies Tourney, Black Belt, page 61, Each year, younger and younger girls line up for competition on the mats, and at this year′s Western Australia Women′s Judo Tournament extra peewee divisions were added to accomodate the young ladies.

Etymology 2

Probably from onomatopoeia of the birds' songs.

noun

1. (Australia, New South Wales and Queensland) A magpie-lark or mudlark (Grallina cyanoleuca).
   A large flock of black and white peewees—magpie larks—passed over our heads from a patch of mangrove[…]. 1939, Francis Ratcliffe, Flying Fox and Drifting Sand: The Adventures of a Biologist in Australia, page 43
   The studies of A. H. Robinson in Western Australia indicate that Peewees tend to pair for life, and hold the same territory on successive seasons. 1964, Carl Weismann, Australian Bird Songs, page 15
   Many Kimberley languages call the peewee or mudlark diyadiya (pronounced like ‘dear-dear’) after one of its calls;[…]. 2004, William McGregor, The Languages of the Kimberley, Western Australia, page 2
2. A pewee.