It’s not usually a good idea to look up when seagulls are overhead, but I did that at Nimbus Flat (Folsom Lake SRA) and caught them swirling and singing above peak valley oak.
Several thousand seagulls have been spending late autumn on Lake Natomas (formed by Nimbus Dam on the American River in Folsom) on their way to the coast. California gulls breed during summer on isolated islands at inland lakes such as Mono Lake in the Eastern Sierra. They migrate to spend winter along the coast.
For the past few weeks, a mile-long colony of California gulls has been floating in the middle of Lake Natomas, occasionally lifting off in huge swirling cyclones of squawking seabirds.