Green’s Dictionary of Slang

dicky-bird n.1

also dickey-bird, dickie, dickie bird

1. [mid-19C] a prostitute; esp. as naughty dicky-bird.

2. [mid-19C; 1990s+] a louse.

3. [mid-19C+] a small bird; a chicken or goose.

4. [late 19C] a professional singer.

5. [1900s–40s] (US, also bird) an informer, a betrayer.

6. [1950s] the penis [bird n.3 (1)].