What I know about the California sea gull comes from books and personal experience. They are bold and unafraid to swoop down on unattended French fires at an outdoor restaurant, even if people are seated by the food. The darker sea gulls, called juveniles, take around four years to take on the white and grey look of an adult. Four years! Apparently, and this is the part I have trouble believing, they have a life span, if things go right, of 30 years. Outdoor restaurants beware!