Yes — I agree with you and Lynsey. So hard to find the bird in the viewfinder when they are flying, especially when you're holding a heavy lens, keeping it steady and tracking. These are great shots. I like that you show some of the bird's environment in each of your shots, not just sky behind.

Generally speaking, if you are not getting the whole bird in flight in focus it is probably because you missed on the focus in the first place.  Something that I finally figured out after a lot of shooting.  At f/5.6 you should have plenty of depth of field to capture the entire bird in focus and certainly at f/8.  To get a better feel for this, you might want to play around a bit with a depth of field calculator.  A easy one to use that I have played with is at: http://www.dofmaster.com/dofjs.html  There are also Apps available if you would prefer. One of the greatest advantages of the change from film to digital is that other than the time spent in editing, it doesn't cost you anything to take a lot of shots.  Birds in flight are just hard to get right and I often will throw out 90% of my BIF shots either due to not in focus or just not the right angle or lighting.  This Bald Eagle was about a kilometer away and I fired off a stream of shots to get this.  It was very humid and at that distance there was enough atmospheric distortion that I was pleased with this sharp of a shot. This Bald Eagle was from the same general location but was more like 20 meters away when it unexpectedly appeared and made a pass through the geese I was slowly moving into position to photograph.  I just instinctively pulled up and held the shutter down.