WordNet (r) 3.0 (2006):

queer duck
    n 1: someone regarded as eccentric or crazy and standing out
         from a group [syn: kook, odd fellow, odd fish, queer
         bird, queer duck, odd man out]

Moby Thesaurus II by Grady Ward, 1.0:

31 Moby Thesaurus words for "queer duck":
   alien, case, character, crackpot, crank, eccentric, fanatic,
   hermit, hobo, kook, lone wolf, loner, maverick, meshuggenah,
   natural, nonconformist, nut, odd fellow, oddball, oddity, original,
   outsider, pariah, queer fish, queer specimen, rara avis, screwball,
   solitary, tramp, type, zealot