Lee, Parr, Hwang, Mindell,& Choe (2003):
Phylogeny of magpies (genus Pica) inferred
from mtDNA data. Molecular
Phylogenetics and Evolution 29: 250–257.
Hypothesis before 2000:
Late Pleistocene:
American Pica extinct, only
survived in California – later nutalli
Pica pica