Raptor droppings

I'm afraid so! All birds, reptiles, amphibians and one group of mammals, the monotremes (echidnas and the platypus), have a single posterior orfice called the cloaca. (Apparently also known as the 'vent' in birds).
The cloaca is a multi-use orifice that serves as the opening for the urinary, intestinal and reproductive tracts. Interestingly some species of bird possess a phallus, while others do not, those without will inseminate a female by touching their cloacae together.
So when birds defecate, it is a mixture of both intestinal waste and metabolic wastes, the bird droppings I see are always that instantly recognisable mix of brown and white, with the brown/green portion being the fecal matter, while the off-white portion represents the metabolic wastes, which in a mammal would be present in the urine. I assume that the consistency of this will also shift depending on water consumption.