When I got this picture of a flock of Ibises in flight I was surprised at the black wing tips. The birds look white when they're standing on the ground. After I took this picture, I noticed in the photo above that the black wing tips are showing a little on the bird on the left. The birds are too skittish to get close to, so I get my best look at them in the pictures I take.
Check out the wingspan in this juvenile Ibis: