Gulls are often thought of as coastal birds, but California Gulls are also common in inland areas in the West. These medium-sized gulls breed in colonies on islands and levees in lakes and rivers. You'll also spot them in pastures, scrublands, and garbage dumps as they often forage miles from the colony, eating everything they can find from mayflies to garbage. In the winter they head to the coast where they cruise up and down the shoreline with other gulls.
In the summer, look for California Gulls breeding along inland lakes and rivers, as well as foraging in pastures or parking lots. In the winter they move to the coast where they spend time bathing, drinking, and resting near fresh water. Look for a rivermouth along the coast to find a roosting site. Here you will likely find several gull species, making it easier to judge size and study plumage. Look for a medium-sized gull with yellowish legs and a medium gray back. In flight, look for their deeper and quicker wingbeats than larger gulls, like Herring Gulls, but slower and shallower beats than smaller gulls, like Ring-billed Gulls.
In 1848, a plague of katydids (also known as Mormon crickets) began devouring the crops of Mormon settlers in Utah. When California Gulls returned to breed, they started feasting on the katydids, saving the crops from complete destruction. A golden statue in Salt Lake City commemorates the event, and in recognition the California Gull was made the state bird of Utah.
The California Gull, like most gulls, is an opportunist, eating anything it can catch or scavenge. It has an odd foraging strategy for catching alkali flies that congregate on the shores of salty lakes in the Great Basin. It starts at one end of a huge raft of flies and runs through them with its head down and bill open, snapping them up along the way.
Both parents incubate the eggs, taking turns throughout the day at about 3–4 hour intervals. When it's time to trade incubation duties, an adult flies into the nest area while calling. The incubating gull stands up and gives several "long calls" as its mate lands near the nest. The returning mate joins in the calling and eventually takes over incubation duties. Sometimes the incubating bird isn't ready to leave the nest, so the returning mate offers encouragement by giving the "choking call," presenting nest material, or physically nudging its mate to get it off the nest.
Learning how to fly takes practice and so does learning how to catch something in midair. Young California Gulls practice this skill by dropping a stick in midair and swooping down to catch it.
The oldest recorded California Gull was at least 28 years, 3 months old when it was caught due to an injury in California in 2013. It had been banded in the same state in 1985.