Bulletin of The British Ornithologists' Club 2010 130(4):286-301
47499910

A new taxon of Collared Petrel Pterodroma brevipes from the Banks Islands, Vanuatu

Vincent Bretagnolle, Hadoram Shirihai
Vincent
Bretagnolle
&
Hadoram
Shirihai
292
Bull.
B.O.C.
2010
130(4)
brevipes
south
Vanuatu
magnificens
Cabbage
Tree
O
South
Vanuatu
o
Fiji
A
Banks
#AMNH216923
a
New
Caledonia
[brevipes
Fiji
Figure
3.
Results
of
multivariate
analyses
performed
on
120
specimens
belonging
to
the
P.
leucoptera-brevipes
complex.
Six
biometric
characters
were
used:
wing,
tail
and
tarsus
lengths;
and
culmen,
bill
depth
at
hook
and
bill
width
at
base.
Solid
lines
represent
the
Minimum
Convex
Polygon
(MCP)
including
all
specimens
from
a
given
form.
In
both
cases,
first
and
second
axes
are
presented.
3a)
A
Principal
Component
Analysis
investigates
whether
the
different
forms
split
from
each
other.
3b)
A
canonical
Discriminant
Analysis
is
performed
to
separate
P.
brevipes,
P.
leucoptera
and
P.
b.
magnificens.
MCP
are
also
shown
with
(dots),
or
without
(solid
lines)
outliers
(see
text).
AMNH216923
P.
brevipes
(either
from
other
islands
of
Vanuatu,
or
from
Fiji;
see
Fig.
3a).
The
PC
A
also
suggests
that
AMNH
216923
does
not
belong
to
P.
b.
magnificens.
A
bird
from
Tanna
Island
(AMNH
366704,
a
male
collected
on
2
April
1936)
is
a
strong
outlier.
It
was
collected
with
three
other
birds
on
the
same
day
and
at
the
same
colony;
the
others
are
typical
brevipes
from
Vanuatu.
AMNH
366704
differs
mainly
by
its
relatively
longer
tarsus
and
bill
dimensions.
Original
measurements
made
bv
the
collector
(MacMillan)
agree
very
well
with
our
measurements
(longer
tail,
larger
bill).
We
also
conducted
a
Discriminant
Analysis,
considering
P.
leucoptera
/
caledonica
a
single
taxon,
P.
brevipes
(Fiji
and
southern
Vanuatu)
as
a
single
taxon,
birds
from
the
Banks
a
third
taxon,
and
AMXH
216923
as
a
supplementary
individual
(i.e.,
the
individual
is
not
used
in
the
discriminant
function).
The
results
(Fig.
3b)
also
indicate
that
birds
from
the
Banks
are
at
the
extreme
of
the
range
shown
by
P.
brevipes.
These
statistics
indicate
in
biometrics
P.
b.
magnificens
is
at
the
extreme
range
of
continuous
variation
within
brevipes,
and
is
at
least
distinctive
as
other
close
taxa.
In
particular,
Imber
&
Jenkins
(1981)
supported
separating
P.
/.
caledonica
from
P.
/.
leucoptera
given
its
only
2-3%
larger
mean
bill,
tarsus,
tail
and
wing
lengths.
If
biometrics
might
suggest
clinal
variation
(with
P.
b.
magnificens
at
the
extreme),
the
most
striking
difference
concerns
coloration.
Table
2
compares
the
morphs
of
P.
b.
magnificens
and
other
populations
of
P.
magnificens
Cabbage
Tree
O
Fij
AMNH216923
O
South
Vanuatu
A
Banks
Q
New
Caledonia