The California Department of Fish & Wildlife previously known as the Dept. of Fish & Game, and still using the same web site at www.dfg.ca.gov has made Big Game reporting much easier by providing the hunter the ability to do so on-line.
The report after reporting looks like this, all reporting must be done before Feb 1, so do not leave it too late. Unreported game that the season is still open such as Bobcat or pig should not be reported until the season ends. If you report prior to the end of the season, you may not use those tags to hunt. it says in bold letters on the DFG web site very clearly
DO NOT SUBMIT UNSUCCESSFUL HUNT TAG REPORTS OR PARTIALLY COMPLETED FISHERY REPORTS UNTIL AFTER THE END OF THE SEASON. ONCE YOU SUBMIT A REPORT, YOU MAY NO LONGER USE THE TAG OR REPORT CARD.