The old saying about birds, pigs and rats keeping their own company, turned into a short rhyme with a wink at the end about the speaker having their own tastes too.
From Mother Goose / Nursery Rhymes (traditional). See the whole collection.
Birds of a feather flock together,
And so will pigs and swine;
Rats and mice will have their choice,
And so will I have mine.
Public domain. Text from The Real Mother Goose (Blanche Fisher Wright, 1916), via Project Gutenberg. View the source edition