Editing Animal sexual behaviour (section)

===Birds===

Some black swans of Australia form sexually active male-male mated pairs and steal nests, or form temporary [[threesomes]] with females to obtain eggs, driving away the female after she lays the eggs. More of their cygnets survive to adulthood than those of different-sex pairs possibly due to their superior ability to defend large portions of land.

In early February [[2004]] the ''[[New York Times]]'' [http://query.nytimes.com/gst/abstract.html?res=FA0C1EF83A5F0C748CDDAB0894DC404482 reported] that a male pair of [[chinstrap penguin]]s named [[Roy and Silo]] in the [[Central Park Zoo]] in [[New York City]] were partnered and had successfully hatched a female chick from an egg. Other penguins in New York have also been [http://www.jrn.columbia.edu/studentwork/cns/2002-06-10/591.asp reported] to be forming same-sex pairs.

Zoos in [[Japan]] and [[Germany]] have also [http://www.365gay.com/newscon05/02/021105penguins.htm documented] male penguin couples.  The couples have been shown to build nests together and use a stone to replace an egg in the nest.  Researchers at [[Rikkyo University]] in [[Tokyo]], found twenty such pairs at sixteen major aquariums and zoos in Japan.  Bremerhaven Zoo in Germany attempted to break up the male couples by importing female penguins from [[Sweden]] and separating the male couples; they were unsuccessful.  The zoo director stated the relationships were too strong between the couples.  

Recently, a mated pair of [[swan]]s in [[Boston, Massachusetts|Boston]] were found to both be female. They too had attempted to raise eggs together. [http://www.365gay.com/newscon05/08/081505ramSwan.htm]

[http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2004/02/07/MNG3N4RAV41.DTL Studies have shown] that ten to fifteen percent of female western gulls in some populations in the wild prefer other females.

As many as 19% of Mallard pairs in a given population have been observed to consist of male-male homosexuals.<ref>Bagemihl, Bruce (1999): ''Biological Exuberance: Animal Homosexuality and Natural Diversity'': 479-481. St. Martin's Press. <small>ISBN 0312192398</small></ref>