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:
40,000 years ago Pica
pica re-colonized North America from
Asia
Pica pica