i was just watching ricky gervais' show animals, and there was the bit where he talks about homosexual ones. it's pretty interesting, no? considering the confusion regarding how such behaviour fits in with darwanian evolution.

http://en.wikipedia.org/wiki/List_of_animals_practicing_homosexual_behavior

"An estimated one-quarter of all black swans pairings are homosexual and they steal nests, or form temporary threesomes with females to obtain eggs, driving away the female after she lays the eggs."

:D