bird circuit, n. — Green’s Dictionary of Slang

bird circuit n.

(US gay) touring gay bars in a sucession of cities.

1953		W. Winchell On Broadway 13 Apr. [synd. col.] The liquor authorities have discovered ‘The Bird Circuit’ is the nickname for bars and joynts which invite the patronage of the town’s whoopsies .
1965		Guild Dict. Homosexual Terms 4: bird circuit (n.): Refers to any extended tour of gay bars; generally meaning from city to city.
1972		B. Rodgers Queens’ Vernacular 31: bird circuit sightseeing the gay bars with the purpose of becoming better acquainted with their patrons and locations for future visits.

In phrases

go on the bird circuit (v.)

(US gay) to visit a succession of bars in order to ascertain the whereabouts of the most attractive men.

1989

H. Rawson Dict. of Invective (1991) 43: Male homosexuals also qualify as birds or birdies, and to go on the bird circuit is to make a tour of gay bars across the [USA].