From bird + fucker.
birdfucker (plural birdfuckers)
- (slang, derogatory, offensive, vulgar) Term of abuse.
1997, Larry Niven, Destiny's Road[1], page 305:"Birdfucker!"
2000 November 16, Don Thompson, “Re: REAL election news”, in alt.war.vietnam[2] (Usenet):When you factor in a 12.7mm birdfucker you gain a bit more pucker.
2001 February 1, K, soc.culture.singapore[3] (Usenet):Is that so birdfucker?
2004 June 23, Susan Hogarth, “Re: Liberal = Aristocrat?”, in alt.fan.dune[4] (Usenet):Those birdfuckers* are out to extract just as much or more blood as the American ones.