unp ... did the male bring the fish and then leave with it again?
I looked to see what I might find about Opsrey mating. These quotes were taken (by someone else, from the book Ospreys: A Natural and Unnatural History
by Alan Poole, Cambridge University Press; First Edition edition (March 2, 1989)
Most copulations take place at the nest because females spend most of their time there, but they can occur anywhere.
No elaborate ritual or display precedes mating.
Females sometimes appear to solicit copulations by tipping forward with raised tail and dropped wings (Sailler, 1977), but this is subtle behavior and hard to decipher. (also- unless the female tips forward at 45 degrees, the mating is not "real")
At other times, it seems that the males mount with no signal from from their mates, flying in from behind (like Yeat's Zeus landing on Leda) or fluttering up onto the female from the nest edge.
Pairs mate most frequently just prior to egg laying. Earlier copulations may have little to do with fertilization, serving instead to test a mate's receptiveness (strengthen the pair bond) and to synchronize the development of the gonads
. This latter aspect is especially important because females probably arrive back at nests each year with ovaries only partially developed, then going through a period of rapid ovarian development. In this phase, ovaries gain 5 to 15 times their initial weight before descending the oviduct (Lofts & Murton, 1973)."