Some birds are really difficult to catch up close. Even more difficult is trying to catch a bird flying. At this job it is easier to catch larger birds like Eagle or Osprey or bird that fly slow like Seagull. With modern DSLR the automatic focus on continuous mode is quite a help but even with that you need luck and patience. I wonder what they were doing before automatic focus. I will spare you all the missed try at capturing an Osprey in flight. This is my best shot I was able to get but still not exactly what I wanted, I think it spotted me on the first one. I hope to be able to catch one diving for a fish one day.