Green’s Dictionary of Slang

bird n.2

[echoic of a harsh bird-call]

1. [early 19C+] (US, also big bird) a loud, derisive noise, imitative of a fart.

2. [20C+] one who deserves ridicule.

3. [1900s] (Aus.) one who has been dismissed from a job.

4. [1920s+] any form of ridicule or derision.

5. in non-theatrical sense, an act of rejection, e.g. of courtship.

6. [1960s+] (US) usu. as the bird, an obscene gesture of dismissal, mockery; usu. in v. phrs below.

In phrases

flip a/the bird (v.) (also bird, flick off, flip off, flick the bird, fly a/the bird)

1. [1950s+] to make an obscene gesture by raising the middle finger from the otherwise clenched fist.

2. [1980s] in fig. use.

get the (big) bird (v.) (also have the bird) [the image of the hissing noise that geese, and an unappreciative audience, can make]

1. [early 19C+] esp. theatrical use, to be jeered, mocked etc .

2. [late 19C+] to be dismissed, usu. from a job.

give someone a/the (big) bird (v.) (also hand someone a/the bird) [late 19C+]

1. to express one’s disapproval vocally, esp. by hissing; also in fig. use.

2. to raise the middle finger as a gesture of derision.

3. to reject, to dismiss.

have a bird (v.)

[1980s] (US) to become very angry.

shoot a/the bird (v.)

[1960s+] (orig. US) to make a mocking, derisory gesture by clenching the fist and raising the middle finger.