Actually it was the 2003 igNoble prizes:

BIOLOGY
C.W. Moeliker, of Natuurmuseum Rotterdam, the Netherlands, for documenting the first scientifically recorded case of homosexual necrophilia in the mallard duck.
[REFERENCE: "The First Case of Homosexual Necrophilia in the Mallard Anas platyrhynchos (Aves: Anatidae)" C.W. Moeliker, Deinsea, vol. 8, 2001, pp. 243-7. Photographs can be viewed at ]
WHO ATTENDED THE IG NOBEL CEREMONY: Kees Moeliker.

The original publication was 2001.

A