Nothing to do with Nurture?

"In the idyllic setting of the Wildfowl and Wetlands Trust in Slimbridge, 325 hectares of Gloucestershire wetland alive with water voles and dragonflies and the world's largest collection of swans, geese, and ducks, live a pair of gay flamingos named Carlos and Fernando.

Together for six years, they have raised three chicks after stealing eggs from other couples, feeding them by producing milk in their throats. This week, the pair were given the responsibility of raising a newly hatched flamingo that has been rejected by its mother."

Article from The Guardian.