All the photos below taken using Olympus E-3 and Zuiko 70-300.
Most of the time i use natural color +1 sharpness
Iso is a tricky part as u need fast shutter speed to have sharp picture..so i dont hesitate to use up to iso 1000
locating the birds are hell of a difficult thing to do..
i use the following method:-
1. listen to the bird sound to hear the direction of the bird.
2. then try to locate them visually..or can use your viewfinder cause the magnification helps.
3. slowly try to walk as close as possible to them and snipe away!!