Kingfisher New Background

I had some reasonable shots of a Kingfisher but they had a pretty uninspiring grey background due to a dull overcast day. So for the very first time I decided to find out how to change the background of the shot, this is the result not perfect by any means but more pleasing to the eye than grey. There is also a slight vignette, it's obviously not a natural background and I would always say if I had done this. Any thoughts ?

Done