Green’s Dictionary of Slang

1. a woman.

1881		Newcastle Courant 16 Sept. 6/5: Sam [...] stayed to speak to his ’twitter’ [...] and enjoined her to follow him.
1914		Sport (Adelaide) 11 Sept. 4/2: Butt S. and Herb N. think they are very flash talking to two twitters in front of the big furniture shop.

2. either an effeminate man or a masculine woman.

1909

J. Ware Passing Eng. of the Victorian Era.