Very nice and sharp images no matter what lens you used.
Coming from the master of sharp bird images, I take that as a high compliment Tom! The Sigma 70-300 APO DG has a sweet spot (as Mtnman also remarked) at about 280mm and a couple of stops down from wide open. I also shot #1 and #3from a tripod mount and the remote shutter release to avoid any camera vibration. # 2 was done with hand holding and breath holding as well!