I've noticed the birds in San Francisco seem to change their flight patterns in the fall. I know that migration is related to food availability, and there's plenty of that in the City, year around, so they're not migrating. But they do seem to fly around in big swooping flocks and land in new places. Last year I noticed dozens of birds on the lines around Bernal Heights and promised this year I would carry my camera to capture them. Maybe they're stopping in on the way down South from Canada. In this shot, my neighborhood pigeons are hanging out, where I can count on seeing them year around.