Or try the Canon 400mm f5.6
Pros
Reasonably priced, not too heavy and speedy AF along with very sharp images.
Cons
No IS, shutter speed needs to be kept up if hand holding (not an issue with birds in flight) and only manual with a T/C unless on a Series 1 body
Just got one after some research, would have liked the 500mm f4, but couldn't find an extra 4 grand down the back of the settee
Not a term I like using, but provides the best bang for the buck in my opinion