While discovering the secrets of Treasure Island, Erik and I came across a number of pelicans diving for fish just off the breakers at the western part of the island. Seeing how we live in Potrero Hill, which is very much lacking in pelicans, we thought this qualified as an "irregular animal."

It was very neat to watch them. The was a strong wind and the birds would ride the thermal currents up and down. We noticed that when they straightened their bodies out and hung in the air motionless for a moment that it meant they were getting ready to dive. And dive they did - straight in the water with a big splash. Because of the angle of the sun, it was a bit hard to tell if they caught any fish. But they seemed to be having run riding the currents and diving.

An internet search upon returning home showed that we saw Pelecanus occidentalis californicus or the California brown pelican. Wikipedia states that "This bird is distinguished from the American White Pelican by its brown body and its habit of diving for fish from the air, as opposed to co-operative fishing from the surface. It dines mostly on herring-like fish. Groups of these birds often travel in single file, flying low over the water's surface." Which is indeed the behavior we observed.