When it it pulled in the other direction, it looks like a goose and the chicks continue feeding. The instantaneous collective response I had witnessed was probably generated by the genetic structure of the gulls and had probably been locked in as an instinctive behavior over the past ten million years. The Peregrine flew to the end of the flock then turned and flew alongside it. He made a few feints at individual gulls and then, just as he reached the beach, he swooped down at one which was close to the sand. He missed on all three of these attempts, which was not surprising since the gulls were all highly aware of his presence.
Predators usually count on surprise in order to capture prey.
I lost him as all the birds moved out to sea. A few minutes later, however, the peregrine came back, flying over the lagoon in the opposite direction from before. At the upper end, he began to soar in circles, rising higher and higher. He got smaller and smaller in my binoculars and when I dropped them momentarily, I couldn't see him with my naked eye. Nor could I find him again in the glass when I tried.