And a few of these:
This is a pellet made up of Pelagic Red Crab pieces. (Many birds cough up pellets of indigestible prey parts.)
I'm not sure which species of bird ate these Pelagic Red Crabs, but my guess would be a gull. Herring Gulls (Larus argentatus) and Western Gulls (Larus occidentalis) have been documented feeding on Pelagic Red Crabs in southern California during previous El Niño years (Stewart et al. 1984).
P.S. I've written about pellets before — for examples, see "Identify the Prey in the Pellet" on 25 November 2014, and "Rounded and flattened" on 2 November 2015.