Theres no reason to have to use a lead-free bullet, just make sure you follow the rules below.

This is out of the Fish and Game Book:

If you hunt in California condor range, you are being asked to get the lead out. Following reports that lead ammunition is contributing to the high lead levels documented in some wild condors, the DFG and other conservation groups are asking for hunters in condor range (parts of the counties of Tulare, Kern, Los Angeles, Ventura, Santa Barbara, San Luis Obispo, Monterey, and San Benito) to remove lead from the area by following a few simple steps:
-Retrieve all killed animals (including coyotes and small game)from the field, or
-Hide carcasses or gut piles by burying them, covering them with brush or rocks, or placing them in an inaccessible area, or
-Remove bullets and surrounding impacted flesh when leaving carcasses or gut piles in the field, or
-Use lead-free ammunition, in which case none of the above is needed.