There is a small colony of Northern Cardinals establishing from the cage bird trade (most likely from Tijuana). The population is far from being large enough to be "countable" under ABA guidelines.
These birds are from the eastern US subspecies of Northern Cardinal. Were they to be of the subspecies that is resident in Arizona countability would be questioned. One thing to look for in regards to the subspecies is the amount of black on the face, with those in Arizona having much less than their eastern counterparts.
San Diego County, California, US