I spent an afternoon at the Merced NWR trying to photograph Ross Geese, who spend their winter here in large numbers (something like 50-60k). Most of the time, I was waiting by a seasonal pond waiting for them lift-off while listening to their noisy cryptic chatter. There were few anxious moments when it looked like they may take off in large numbers, but nothing really happened.
As dusk approached, they started to fly away in small groups to a nearby field far away from the road and it looked like they were going to spend the night there. But something spooked them right after the sun went down, they screamed past me in a large circle and most of then flew back to the filed from which they took off. I had given up all hope, and was concentrating on some sunset reflections shots, when my wife alerted me to a low rumble from the distant filed, and I turned around in time to see the large cloud of birds lift-off once again and came flying back to the pond there were in before. Its hard to describe the scene with words, so take a look at the video below. I shot this before and after I made this photo.