When you get this lens, remove the tripod bush and put it back in the box. You won't be needing it. This is just a brilliant lens to leave on your camera body and have slung over your shoulder when you are out birding. When the opportunity presents itself ie: nice light, obliging bird, close fly by, just point and shoot away.
In other words the perfect travelling companion. By the way it doesn't have IS.....who needs it !!