Speciation and sub-speciation of Northern Hemisphere magpies seems to be
quite complex. The sequencing of mitochondrial DNA by Lee et al. (2003)
suggests that the North American Black-billed Magpie (Pica hudsonia) which
looks almost identical to the Eurasian Magpie (Pica pica), and was
previously considered conspecific, is genetically closer to the other North
American species, the Yellow-billed Magpie (Pica nutalli). The main Eurasian
lineages have not been sufficiently sampled to clarify the status of such
forms as the north-west African race (P. p. mauretanica) and the south-west
Arabian race (P. p. asirensis), which could also be distinct species. The
Korean race (P. p. sericea), is very distinct genetically from the other
Eurasian forms, and may also be a separate species.
The genetic work of Lee et al. (2003) does not seem to have been taken into
account by the BirdLife database. Therefore, I would agree with Mike that
the bird at Port Hedland is more likely to be the Eurasian Magpie (P. pica)
than the Black-billed Magpie (P. hudsonia).
I've pasted the title and abstract of Lee et al. below.
Kind regards,
Stephen
Dr Stephen Ambrose
Ambrose Ecological Services Pty Ltd
Ryde NSW
Lee, S, Parr, CS, Hwang, Y., Mindell, DP & Choe, JC (2003). Phylogeny of
magpies (genus Pica) inferred from mtDNA data. Molecular Phylogenetics and
Evolution 29: 250-257.
Abstract
We investigated the phylogenetic relationships of species and subspecies of
the cosmopolitan genus Pica using 813 bp of the mitochondrial genome
(including portions of 16s rDNA, tRNA-Leu, and ND1). The phylogenetic
relationships within the genus Pica revealed in our molecular analyses can
be summarized as follows: (1) the Korean magpie (Pica pica sericea) appears
basal within the genus Pica; (2) the European magpie (Pica pica pica) shows
a close relationship to the Kamchatkan magpie (Pica pica camtschatica); (3)
two North American species (Pica hudsonia and Pica nuttalli) shows a
sister-group relationship; (4) most importantly, the European + Kamchatkan
clade appears more closely related to the North American clade than to
Korean magpies. Based on these results and genetic distance data, it is
possible that members of an ancestral magpie lineage in East Asia initially
moved north to form Kamchatkan magpies and then crossed the Bering land
bridge to found North American taxa. At a later date, a group might have
split off from Kamchatkan magpies and migrated west to form the Eurasian
subspecies. The divergence between the two North American taxa appears to
have happened no later than the divergence of Eurasian subspecies and both
processes appear to have been relatively rapid. Rather than the formation of
P. hudsonia by re-colonization from an Asian magpie ancestor, as suggested
by Voous (1960), our data suggest a shared ancestry between P. hudsonia and
P. nuttalli. Based on the above findings, including phylogenetic placement
of P. hudsonia and P. nuttalli as nested within the larger Pica pica clade,
and the lack of evidence suggesting reproductive isolation within the genus
Pica, we believe that the current classification may be inaccurate. A more
conservative classification would recognize one monophyletic species (i.e.,
P. pica) and treat P. nuttalli and P. hudsonia as subspecies (i.e., P. p.
nuttalli and P. p. hudsonia). More extensive studies on the population
genetics and biogeography of magpies should be conducted to better inform
any taxonomic decisions.
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