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
291
Bull.
B.O.C.
2010
130(4)
TABLE
2
Comparison
of
degree
(by
%,
see
Watling
1986)
of
ventral
darkening
between
P.
b.
magnificens
and
other
Collared
Petrel
P.
brevipes
populations:
the
scale
is
illustrated
using
specimens
(Figs.
1)
and
birds
photographed
at
sea
(Figs.
4-11).
Data
are
drawn
from
the
following
samples.
1.
P.
b.
magnificens:
Banks
Islands,
northern
Vanuatu
(n=5),
including
the
holotype,
all
held
at
AMNH
(note
1:
the
20%
'smoky'
pattern
involves
the
borderline
case
AMNH
216920,
which
could
be
described
as
'dark
grey'
but
some
P.
b.
magnificens
can
appear
a
shade
paler
grey
below).
2.
P.
b.
magnificens:
live
birds
scored
off
the
Banks
Islands,
northern
Vanuatu,
in
December
2009
(Appendix
2)
when
180
sightings
of
P.
b.
magnificens
all
involved
birds
that
were
dark
ventrally,
but
only
57
could
be
properly
evaluated
for
this
analysis,
as
either
'dark
grey'
or
'extreme
dark
grey'
(note
2:
the
10.53%
'smoky'
pattern
involves
six
borderline
birds,
which
could
be
categorised
as
'dark
grey'
but
are
treated
as
'smoky'
because
some
P.
b.
magnificens
can
appear
slightly
paler
grey
below).
3.
P.
brevipes:
other
populations
from
Fiji
and
Vanuatu,
specimens
from
AMNH,
the
Natural
History
Museum,
Tring,
and
the
University
Museum
of
Zoology,
Cambridge,
UK
{n-26).
4.
P.
brevipes:
live
birds
captured
and
scored
on
Gau
Island,
Fiji
(n=140)
by
Watling
(1986)
(note
3:
Watling
1986
did
not
divide
scored
birds
into
'dark
grey'
or
'extreme
dark
grey').
5.
P.
brevipes:
live
birds
scored
at
sea
off
Gau
Island,
Fiji
(n=98)
during
the
Fiji
Petrel
Pseudobulweria
macgillivrayi
expedition
(Shirihai
et
al.
2009;
pers.
obs)
(note
4:
the
2.04%
'extreme
dark
grey'
involves
two
borderline
cases
with
an
underwing
pattern
almost
as
in
the
'extreme
dark
grey'
type
but
their
underparts
were
still
rather
pale.
Pure
white
Grey
Smoky
Dark
grey
Extreme
dark
peppering
grey
1.
P.
b.
magnificens:
type
series,
Banks
0%
0%
20%
1
40%
40%
Islands,
northern
Vanuatu
(n=5)
2.
P.
b.
magnificens:
birds
at
sea
off
Banks
0%
0%
10.53%
2
47.37%
42.11%
Islands,
northern
Vanuatu
(n=57)
3.
P.
brevipes:
other
populations
from
Fiji
50.00%
23.08%
11.54%
15.38%
0%
and
Vanuatu.
Museum
specimens
(n=26)
4.
P.
brevipes:
live
birds
captured
on
Gau
37.00%
17.00%
29.00%
17.00%
c
?
3
Island,
Fiji
(n=140)
5.
P.
brevipes:
live
birds
at
sea
off
Gau
37.76%
21.43%
23.47%
15.31%
2.04%
4
Island,
Fiji
(n=98)
Fijian
or
other
Vanuatu
populations
of
brevipes
by
4.6-5.8%
and
4.4-6.1%,
respectively.
It
is
also
consistently
shorter
winged
(by
2.9-3.4%),
but
less
so
in
tail
(up
to
1.3%
shorter
than
some
populations,
but
0.4%
longer
than
P.
brevipes
in
Fiji
and
Vanuatu).
Thus
P.
b.
magnificens
appears
elongated
posteriorly
with
a
relatively
longer
tail
but
short
rounded
wings,
which
are
especially
appreciable
in
flight
(Figs.
8-12).
Its
bill
depth
and
width
are
similar
to
other
populations
of
P.
brevipes
on
Fiji
and
Vanuatu.
As
the
only
specimens
available
from
Gau
Island,
Fiji,
are
preserved
in
liquid
(Suva
Museum,
Fiji)
we
could
not
measure
these
birds,
but
measurements
were
presented
in
Watling
(1986).
P.
b.
magnificens
also
differs
from
birds
on
Gau
in
its
10.51%
shorter
culmen,
1.4%
shorter
wing
and
6.21%
shorter
tail.
Tarsus
(mean
26.1
mm)
as
measured
by
Watling
(1986)
for
birds
from
Gau
is
much
shorter
than
any
other
population
of
P.
brevipes.
We
assume
that
this
reflects
different
measuring
protocols
and
therefore
do
not
compare
our
data
with
his
for
tarsus
length.
Using
the
120
specimens
measured
by
VB
in
various
museums
(see
Acknowledgements
and
Appendix
1)
permitted
further
statistical
analyses.
Wing
and
culmen,
and
to
a
lesser
extent,
tarsus,
differ
significantly
between
the
six
birds
from
the
Banks
(treating
AMNH
216923
apart)
and
all
other
P.
brevipes
(Table
1).
Then
we
used
a
Principal
Component
Analysis
(PCA),
a
multivariate
analysis
that
permits
using
all
of
the
biometric
parameters
simultaneously.
The
PCA
revealed
that
the
birds
from
the
Banks
are
well
separated
from
all