Consolidation and Modification of Sexual Preferences in Adult Male Zebra Finches

In a previous study (KRUIJT & MEEUWISSEN, 1991) we examined the sexual preference of cross-fostered zebra finch (= Z) males that were reared by Bengalese finch (= B) parents and then isolated until the adult stage. Males then given a choice between a Z and a B female, directed most courtship and song to B. After subsequent social experience with a Z female in a breeding situation, these males showed a shift in preference to Z, though still preferring B. If, instead, Z males had social experience with Z in a breeding situation without being put in choice tests before, the subsequent preference was for Z, so modification of preference was stronger, suggesting that prior exposure and courtship to B had consolidated the effects of early experience with foster parents and had reduced the possibility for modification.The present study concerns Z males reared by conspecific parents, with the aim of examining whether the results of the previous study were influenced by an own species bias. Again, males either obtained the opportunity to express their preference in choice tests before social experience in a breeding situation with a female of another species (B), or not. The results were similar to those of cross-fostered males in that: (1) prior exposure to a female of the rearing species during choice tests resulted in consolidation of preference for the rearing species; (2) social experience in a breeding situation with B resulted in a modification of preference in the direction of B, which was stronger without prior consolidation; (3) shifts of preference were not related to breeding success; (4) the effects of consolidation and modification remained present for over 1 year, although preferences gradually shifted in the direction of the rearing species; (5) the shifts of preferences due to both types of rearing condition mirrored each other, so, no evidence was obtained for an own species bias. From a similar study, BISCHOF & CLAYTON (1991) concluded that an own species bias is present in cross-fostered Z males. Their finding might be due to the presence of more siblings during the rearing of cross-fostered males than in our study, but this is uncertain without further experimentation.