Green’s Dictionary of Slang

1. nothing, an insignificant amount, foolish talk.

1960

I. Freeman Out of the Burning (1961) 122: That’s bird turd till the court gives the word. You don’t search this joint without a big-ass warrant.

2. an insignificant, worthless person.

1971

B. Malamud Tenants (1972) 90: Suppose those birdturds come back here today?