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
290
Bull.
B.O.C.
2010
130(4)
starting
just
above
dark
lores
in
front
of
eve.
Upper
ear-coverts
and
area
around
eve
and
upper
forehead
onto
crown
/
nape
blackish
with
sooty-brcnvn
0
hue,
slightly
darker
blacker
than
rest
of
upperparts.
Much
of
upperparts
very
dark,
the
larger
'outer
scapulars,
tertials,
back
and
rump,
smaller
uppenving-coverts
and
uppertail
being
predorninatelv
dusky
brown
7
,
whilst
mantle
and
smaller
/inner
scapulars
and
larger
uppenving-coverts
paler
due
to
presence
of
extensive
blue-grey^
bases
(with
brownish"
tips);
latter
form
scaly
pattern.
Uppertail-coverts
paler
(mid)
blue-grey
10
,
approaching
tone
of
underparts,
and
contrasting
with
dark
grev-brown
11
rectrices.
Only
folded
wing
can
be
described,
but
dorsal
contrast
suggests
the
new
taxon
has
only
a
relatively
moderately
developed
upperwing
M
pattern
12
.
Undenting
pattern
impossible
to
describe
from
folded
wing,
but
most
of
larger
coverts
and
flight
feathers
predominantly
dark
grey
13
,
without
any
visible
paler
grey
or
whitish
bases
and
inner
webs
to
remiges.
Lesser
primarv-coverts
carpal
area
and
secondary-coverts
form
a
black
14
area
conirasting
with
whitish
lr
inner
coverts,
axillaries
and
median
secondary-coverts.
Much
of
breast
and
belly
dark
ashv
slate-grev
lr
,
becoming
slightly
more
uniform,
darker
1
'
and
more
solid
on
breast.
Narrow
pale
feather
tips
on
bellv,
rear
flanks
and,
especially,
around
legs
to
undertail-coverts
produce
slightly
paler
grev-
and
less
uniform
(more
flecked)
appearance,
but
do
not
disturb
overall
dark
and
uniform-
looking
underparts.
Original
label
states
iris
colour
as
'brown'
and
bill
'blue',
but
bill
and
feet
are
now
black
19
,
and
tarsal
skin
brownish
20
.
Die
case
o
f
AMXH
216923.
R.
Beck
collected
seven
specimens
at
the
same
location
(in
two
days).
While
the
seven
birds
should
be,
at
hrst
glance,
considered
a
single
sample,
one
specimen
shows
striking
differences.
Indeed
Beck
collected
a
single
pale-bellied
bird,
AMNH
216923
(see
Fig.
2).
In
addition
to
being
the
only
pale
bird,
this
specimen
is
also
larger
(wing
223
224
mm,
tail
107
mm,
exposed
culmen
24
mm
and
tarsus
27.5
mm).
Finally,
unlike
the
other
six
specimens,
this
specimen
had
'small',
i.e.
undeveloped
sexual
organs.
We
thus
tentatively
conclude
that
it
was
a
non-breeding
wanderer
from
another
P.
brevipes
population,
probably
southern
Vanuatu,
where
P.
breoipes
are
larger
overall
compared
to
birds
from
the
Banks
(see
below).
During
December
2009
no
similarly
plumaged
P.
brevipes
were
observed
(see
below),
further
suggesting
that
any
other
pale
CookiJarui
must
be
rare
in
these
waters,
at
least
at
this
season.
Diagnosis.
P.
b.
magnificens
differs
from
all
populations
of
P.
brevipes
/
leucoptera
according
to
morphometries
and
most
importantly,
plumage
(see
Table
1
for
biometric
data
for
P.
b.
magnificens
and
all
other
populations,
and
Table
2
for
coloration).
In
mean
values,
the
bill
(exposed
culmen)
and
tarsus
length
of
P.
b.
magnificens
is
consistently
smaller
than
6
RAL
7012/Basalt
grey
&
8022
/Black
brown
=
CSS
3e332f
&
040ela.
7
RAL
8011
/Nut
brown,
8022/Black
brown
&
5004
Black/blue
=
CSS
lbldl2,
332f2c
&
262217.
8
RAL
7016
Anthracite
grey
=
CSS
293138.
9
RAL
8019
Grey
brown
=
CSS
201
Fl
7.
10
RAL
5007
Brilliant
blue
=
CSS
4E543D.
11
RAL
7021
/Black
grey
(mostly
outer
webs)
&
8022
Black
brown
(mostly
inner
webs)
=
CSS
1
10d02
&
21231e,
respectively.
1:
RAL
8022/Black
brown
=
CSS
060803.
1?
RAL
7026
/Granite
grey
=
CSS
716771
14
RAL
9004/Signal
black
=
CSS
0e0d09.
15
RAL
9010/Pure
white
=
CSS
f9fafc.
16
RAL
7012/
Basalt
grey
=
CSS
45453C.
1_
RAL
7021
Black
grey
=
CSS
302c2d.
18
RAL
7037
Dusty
grey
=
CSS
635d5f.
1U
RAL
9011
Graphite
black
=
CSS
040f0b.
:o
RAL
8028
Terra
brown
=
CSS
3b2d22.