No no no no no! Noooooo. IS is so important for wildlife. Many many great wildlife activity and sightings happen in low light and IS is paramount in those situations…. Not all wildlife photos are hunting cheetahs! And it gets worse in ever green forests like India and Costa Rica…
Nah, its helpful but really once you get down to the point that IS becomes necessary the movement of the bird will blur the shot. Its extremely difficult no matter what equipment you have to shoot in heavy forest. You really need to use a flash in those cases, both for illumination and to freeze motion.
+1 to Sanj. The little birds etc don't move perpetually but do have periods of keeping still, which is why you can get sharp shots at 1/15s etc. IS is very useful and expands the range of what is possible. I could not go back to non-IS now.