I have to suggestions for moving a finely detailed bird to another background

I have an Eagle that I want to move to a different background.  The problem

I have is that the bird's edges are very detailed in spots due to the 
feathers and some of the current background is visible between the fine 
feathers.  I tried selecting using the magnetic lasso but it gets tedious 
quickly when I'm trying to surround these hundreds of fine feathers, plus 
its going to look too sharp once moved to the new background.  Suggestions

for moving this finely detailed bird?  Pointers to any on-line sources
would 
be greatly appreciated.

Thanks,
Sam