Shooting small birds in flight is very difficult at best, most photographers have learned that its a losing battle.
Notice that most of the beautiful bird in flight photos are of large birds. Your first image was taken of a bird that was not flying, my comments did not totally apply to a small bird in flight.
I think you did pretty well with a small bird flying, I'd have to take a lot of shots to capture one in flight.
Here is one that I was lucky to capture with my 100-400L of a female Redwing blackbird as she dropped out of our crab apple tree.