Mark, that is an interesting find and field observation.
Most likely you have an owl talon lacking the keratin sheath.
Strigiformes generally have large talons which are of lesser curvature than their accipiter and falcon cousins.
SoCal birds which prey on other birds (Sharp-shinned, cooper's hawks, kestrels, merlins etc) are much smaller than would be expected with a (de-keratinized) talon of nearly two inches in length. The nearby pile of feathers was most likely from the same bird as the talon you recovered, after it fell prey to another skilled carnivore.
(Owls are particularly sensitive to West Nile virus, so it is possible the carcass of an afflicted bird was discovered by scavengers not predators, of course.)
It would always be helpful to include photos of any other "parts on scene" to help decipher and reconstruct events. Feathers would be a *cough* dead giveaway.
BTW, be careful about collecting and especially displaying ("...a sweet necklace"...) any found raptor/migratory bird parts such as feathers or talons. One would hate to become an example for a zealous enforcement official--and yes, it *has* happened....
See article by John Brooks, US Fish and Wildlife Service:
http://www.gpnc.org/raptors1.htm
From Hawk Watch.org:
"According to the Migratory Bird Treaty Act (Title 50, Parts 10, 13, 14, 17, 21 and 22) it is unlawful to kill, capture, collect, possess, buy, sell, trade, ship, import or export any migratory birds, including their feathers, eggs, and all other parts. Permits are granted by the U.S. Fish and Wildlife Service, and the state in which the permitee resides. Permits are granted for research, rehabilitation, education, religious purposes, and falconry. Other laws that protect raptors are the Eagle Protection Act, the Endangered Species Acts, and other state laws. Violations of these laws are punishable by fines and imprisonment.
While it may seem extreme to punish someone who has found a raptor feather and kept it, it is necessary. Without this extension of the law it would be easier for a poacher to lie and claim that he or she had found the feather on the ground, while in reality they had shot a raptor to obtain the feather.
good luck,
arocknoid