There are a few places where the big birds roam. Of course they fly in from nowhere – and you have the camera somewhere. So out with the camera and on with the zoom lens. Great – now they are so far away that after 10 minutes you remove the zoom and get the 17-50 on again. And a minute later they are really close. Due to the thermic conditions they go really slow. Soom of the vultures did come really close and had a good lock at me. Of course they like to do that when i have the 17-50 mm lens on the camera. Also the eagles can spot the lens and tend to come close than. Still it is great to watch that big birds cruise the sky.