During badminton matches, in very rare circumstances, the shuttlecock (birdie) will fall to rest on the top of the net. I'm not referring to when the shuttlecock gets stuck in the mesh of the net; I'm referring to when the shuttlecock literally lands - feathers down - on the top edge of the net, and continues to rest there without further movement.
This is exceptionally rare, but when it happens, it is usually the result of a lob play that is initiated close to the net and is performed with very low velocity and minimal spin.
Here is a link to video of a great example of this occurring:
What is the correct ruling when this happens, and why?