Same-sex pairs of monogamous birds are just as attached and faithful to each other as those paired with a member of the opposite sex.
The insight comes from a study of zebra finches - highly vocal, colourful birds that sing to their mates, a performance thought to strengthen the pair's bond.
Scientists found that same-sex pairs of finches sang to and preened each other just like heterosexual pairs.
The study is reported in the journal Behavioural Ecology and Sociobiology.
