There is many techniques to do this but the fastest one for me is this::
I open the windmill pic as my background and open the falcon picture on a separated layer and I put a threshold adjustment layer and manipulated the falcon image till I get a black n white rendition, after that I open the magic eraser tool and I erase on the actual layer and that gave me a clean selection of the falcon by it self, after that drag and drop it to the windmill composition and I change the falcon layer mode to darken color and that was it.
here it is

P.S.
the image was kind of grainy so I blur the channels a bit to give a smoother feel, also a curve adjustment to boost the color just a little bit.