I'll bet that got your attention!
A little while ago I was running through a seminar with a colleague. It was an end-of-semester trip through various 'oddities' in the biological literature, including things like the amazing corkscrew penises of mallard ducks & the tendency of some tree shrews to use pitcher plants as potties. 'Hmmm,' said my colleague, 'why don't you include the one about necrophilia by a mallard drake?' I must have given him a rather funny look because he hastened to assure me that this was totally true & had even won an Ig Nobel award for the scientist who described it.
Now, I know that mallard drakes are randy little devils and that groups of them will harass hapless females for forced copulations, particularly later in the breeding season. But this did sound a bit over the top. So, in the interests of completeness & also to check this story for myself, I went looking. and found...
Dr Moeliker works in the Natuurmuseum in Rotterdam. Apparently this building has a all-glass facade - a dangerous thing for the local birdlife, as in certain lights it can act like a giant mirror. It's not unknown for birds to be flying along, minding their own business, & then bang! they fly into the windows & are killed by the collision, whereupon the scientists inside the building often rush out to pick up the corpse & add it to the institution's collection.
Anyway, Dr Moeliker tells of hearing yet another large bang! & rushing downstairs to see if the window was damaged (& also to see what could be added to the bird collection). On the sand outside the building lay a very dead mallard drake - and next to it another drake, this one very much alive. After pecking at the dead bird's head & neck for a couple of minutes, this second bird mounted the corpse & started to vigorously copulate with it (with a couple of brief breaks in activity) for 75 minutes! At this point, Dr Moeliker comments, he 'disturbed this cruel scene'. This apparently disconcerted the necrophiliac drake, who was rather reluctant to leave off what he was doing and hung around, quacking disconsolately, for a good 10 minutes after the human observer had collected the body & stored it safely in the lab freezer. (It was subsequently stuffed and Dr Moeliker relates how it then joined him on lecture tours in Europe & the US.)
And yes, I did include this tale in my seminar - and even managed to deliver it with a (mostly) straight face (although much of the audience was in stitches!).
C.W.Moeliker (2001) The first case of homos*xual necrophilia in the mallard Anas platyrhynchos (Aves: Anatidae). DEINSEA 8:243-247