California Code, Revenue and Taxation Code - RTC § 18741

(a) Any individual may designate on the tax return, under the space labeled “Rare and Endangered Species Preservation Voluntary Tax Contribution Program,” that a contribution in excess of the tax liability, if any, be made to the Endangered and Rare Fish, Wildlife, and Plant Species Conservation and Enhancement Account established in the Fish and Game Preservation Fund pursuant to Section 1770 of the Fish and Game Code.

(b) The contribution shall be in full dollar amounts and may be made individually by each signatory on a joint return.

(c) A designation under subdivision (a) shall be made for any taxable year on the original return for that taxable year, and once made shall be irrevocable.

(d) The Franchise Tax Board shall revise the form of the return to include a space labeled “Rare and Endangered Species Preservation Voluntary Tax Contribution Program” to allow for the designation permitted under subdivision (a).

(e) A deduction shall be allowed under Article 6 (commencing with Section 17201) of Chapter 3 of Part 10 for any contribution made pursuant to subdivision (a).