Many years ago I caught a winter fish with what could only have been the entire wing of a water ouzel in his stomach. The bones and the quills of the wing feathers were intact though partially dissolved by the steelhead's digestive juices. These small birds do have the habit of searching for food underwater, essentially walking with their wings spread in such a way that the current holds them down on the bottom. On another occasion I caught a very late-run hen on the Dungeness (this was years ago when it was still open in May). She was chrome-bright with sea lice around her vent but her eggs were already loose in the skein and her stomach was packed tight with black flying ants. What an opportunity for a fly fisherman.