On 10th October Johan Ställberg and I saw a
shearwater off Maroubra in Sydney which is
causing us some puzzlement. It was clearly one
of: Streaked Shearwater, pale morph Wedge-tailed
Shearwater or Cory's Shearwater. The first of
these is by a long way the most likely, though a
very early date, but a number of features don't
fit.
Johan was a Magic Point, on the south side of
Maroubra Bay, and I was at Mistral Point, about 1
km away on the north side. It was about 4.30 pm,
and we had strong back light from a lowish sun -
an important point to note in relation to the
notes below. Johan first saw the bird, and phoned
me, not knowing I was at Mistral. The bird was,
he estimated, about 700m from the head, heading
north. I picked it up a few minutes later, in a
stream of hundreds of Wedge-tailed Shearwaters
all heading north into a fresh north-easterly
wind. I watched it for about 15 minutes, as it
came closer, down to about 300m, so I got much
better views than Johan.
I'll focus only on what I consider to be the crucial points:
1) The basic description was that it was a large
shearwater, dark brown above (no hint of an M
mark) and white below, with a wide black border
to the trailing edge of the wing, and black
primaries (thus ruling out Buller's Shearwater).
The primaries and tail above were darker than the
rest of the upperparts. The flight of the bird
was lazy and slow, weaving and banking low to the
water, similar to Wedge-tailed. Bill and leg
colour not made out.
2) The bird was about the same size, or possibly
slightly smaller, than the Wedge-tailed
Shearwaters. Both of us agreed on this point.
This would seem to rule out Streaked, which is
noticeably larger (I've seen seventeen Streakeds,
Johan has seen none). The question that arises
here is whether Streaked at the low end of the
size range is ever this small.
3) I judged the wings, which were held at an
angle similar to Wedge-taileds, to be slightly
broader and slightly shorter than the
Wedge-taileds, though this may have been an
illusion due to the presence of white beneath.
Johan agreed on this point.
4) I had a very close look at the head, and could
not make out any white or streaking on the face
or crown. It appeared to have a uniformly brown
head down to about eye level, and white throat
downwards. The question here is whether the
strong back light may have played tricks,
obscuring the white. My feeling, though, is that
the strong back light was making the white parts
of the birds stand out more rather than less
strongly, very noticeable on the Fluttering
Shearwaters which were passing at the time as
well as on this bird. Johan was unable to see the
head well.
5) The underwing coverts appeared to be pure
white. I could see no indication of any dark
feathering or dark lines, which both Streaked and
pale Wedge-tails show. Johan agreed with this,
but was cautious, as he saw the bird from a
greater distance. The question here is whether
the strong back light might have made such dark
areas invisible. Also, do Streaked and
Wedge-tails sometimes show very little dark
patches on the underwing coverts? There was also
a very thin dark leading edge to the wing, which
Johan also thought that he saw. I judged this
line to be slightly wider at the outer wing.
6) On one occasion, the bird banked quite high
and fanned its tail, which looked medium length
and rounded, quite different from a Wedge-tail,
or, for that matter, a Streaked. I am a bit
cautious about this, as I only saw the tail well
once. I am sure, though, that the tail was not as
long as the Wedge-tails.
These plumage and structural features point to
Cory's, the most outrageous of the three. I'm
certainly not claiming it as such. Cory's of the
Mediterranean and North Atlantic races are bigger
than Wedge-tails, or at least at the upper size
range limit, but there is a subspecies that
breeds at the Cape Verde islands, edwardsii,
which is smaller, and I can't find much
information on that subspecies. It appears never
to have been seen off South Africa.
I'd be happy for any comments on these notes, and
would be more than willing for it to be called a
Streaked, but I suspect it will be one of those
that got away.
Cheers,
Rod
--
Dr Rod Gardner
Senior Lecturer
Department of Linguistics
School of Modern Language Studies
University of New South Wales
NSW 2052
Australia
Tel: ±61 2 9385 1454
Fax: ±61 2 9385 8723
CRICOS Provider Code 00098G
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