On the Herring Gull Behaviour page it is erroneously compared to the California Gull .I have cut and pasted the faulty segment below:
Similar Species
Herring Gull: California Gull is larger, has pink legs, yellow eyes, paler back, and thicker yellow bill. Ring-billed Gull is much smaller, has yellow legs, and a complete black ring on the bill.
Please correct me if I am wrong.