Bwipp, bwipp, bwipp. The pigeons and the sparrows.
Here's a cool video clip of the birds of Downtown Los Angeles' Grand Park Children's Playground. They're regulars at this spot in the afternoon. Mmm... xoichi munchies)) I've seemed to notice that the birds aren't too messy with their poop if they're given a vegetarian diet, as would most commonly be natural for these types of birds. Hopefully it keeps up as the flock's breed and grow larger.