Removal of adult males from the rearing environment increases preference for same-sex partners in the zebra finch

The developmental processes producing preferences for opposite-sex mating partners are not well understood. Zebra finches, Taeniopygia guttata, are colonial and socially monogamous with biparental care. To determine whether the early social environment contributes to sexual partner preference, we removed adult males from breeding colonies when the oldest chicks were less than 1 week old (male-removal rearing) or left them in the breeding cage (control rearing). At independence, male-removal and control offspring were moved to unisex cages. As adults they were given two-choice tests with male versus female stimuli followed by group aviary tests. Male-removal subjects, unlike controls, did not prefer opposite-sex stimuli in the two-choice tests. Male-removal subjects were less likely than controls to successfully pair with opposite-sex birds in the group aviary tests; 38% of them paired with a same-sex bird. Thus early social experience may contribute to a critical component of mate choice, choosing the opposite sex, in this pair-bonding species. (C) 2000 The Association for the Study of Animal Behaviour.