Gulls should be called that and not seagulls.

Here in inland Alberta, 'seagulls' are a sure sign that spring has arrived. They follow the river systems from south to north all over North America.
We live near a reservoir and the South Saskatchewan River. Many thousands come here in the summer. During the day the gulls feed in fields and garbage dumps, at evening they fly to water to roost for the night.
It is pleasant to sit outside on summer evenings and listen to their flights as they go overhead- they 'call' continuously.

The California 'seagull' is one of our summer breeders, common in western Canada from British Columbia to Manitoba, as it is all over the western U. S.
It breeeds inland, not in California. It goes to California only as a snowbird.

It could just as easily be the state bird of any western state (or western Canadian province).