Practically Ospreys feed exclusively on fishes but there are a few recorded cases when Ospreys hunted, ate or possibly took nonfish prey perhaps to decorate their nest. These records include birds, snakes, voles, squirrels, muskrats, salamanders, a small alligator and even conchs which Ospreys opened (and ate) by dropping them onto a concrete-filled steel drum.

I am not aware of any published (or not published) record of Ospreys hunting crabs. Please sent me a note if you know about any record of Osprey taking this kind of prey.

Poole et al. (2002) speculated that some of these reports include nonfish taken in water and Ospreys were probably using typical foraging techniques (e.g., alligator, muskrat) emphasizing the generalist nature of Osprey predation while hunting over water. In my observed case the Osprey used completely different technique of approach and strike the crab compare to techniques Ospreys are using when hunting fish. I am still in process of checking published literature and working on describing this event. Hopefully I will finish soon and will be able to present the results. As here we deal with juvenile Osprey on wintering grounds there is no possibility of taking crab to the nest.