Also, two male ducks, one of them dead, a scientific paper, 2001:
"Moeliker, C.W., 2001 – The first case of homosexual necrophilia in the mallard Anas platyrhynchos (Aves: Anatidae) – DEINSEA 8: 243-247 [ISSN 0932-9308]. Published 9 November 2001"
http://www.hetnatuurhistorisch.nl/fileadmin/user_upload/docu...
The talk about it:
https://www.ted.com/talks/kees_moeliker_how_a_dead_duck_chan...
"Kees Moeliker: How a dead duck changed my life"