California Fish And Game Code Section 2016

It is unlawful to enter any lands under cultivation or enclosed by a fence, belonging to, or occupied by, another, or to enter any uncultivated or unenclosed lands, including lands temporarily inundated by waters flowing outside the established banks of a river, stream, slough, or other waterway, where signs forbidding trespass are displayed at intervals not less than three to the mile along all exterior boundaries and at all roads and trails entering such lands, for the purpose of discharging any firearm or taking or destroying any mammal or bird, including any waterfowl, on such lands without having first obtained written permission from the owner of such lands, or his agent, or the person in lawful possession thereof. Such signs may be of any size and wording, other than the wording required for signs under Section 2017, which will fairly advise persons about to enter the land that the use of such land is so restricted.