Congratulations Simon. What a great discovery and I hope it is new taxa.
You might find the following anecdote of use on your next trip
From 1993 to 1999 Pat and I were Kimberley commercial fishers (Beche de
mer and Spanish Mackerel) where we lived at sea for most of the year.
About every 6 weeks we would sail to Darwin to unload our catch and
refuel.
Returning from Darwin our route to the Kimberley would take us via
Charles Point and Fish Reef and then up to 100Nm off shore across the
Boneaparte Gulf on what we knew as Route 222 (222Nm) on a bearing of
approx 250 mag. from Fish Reef to Cape Londonderry. Interestingly this
course runs approximately 30 Nm south of Flat Top Bank where you have
found the “Arabian Shearwaters”
Anyway, particularly during the dry season, the Boneapart Gulf (known by
local sailors as the Blownapart Gulf) is barren regarding pelagic
birdlife although occasionally we did see some interesting stuff. But
usually in about the third week of October the Gulf comes alive with
birds as tuna schools move in. Almost overnight Shearwater flocks often
comprising many hundreds of birds appear. They seem to be attracted to
the fish schools when they regularly irrupt into a surface feeding frenzy.
The species composition of the shearwater flocks were usually mixed
comprising Streaked (about 25%) and making up the bulk of numbers, what
I had always thought until your find, to be Hutton's Shearwater.
Numerous terns, mainly Lesser Crested, Bridled and Roseate are often
picking around the margins and occasionally I would see all dark medium
sized petrels, probably Bulwer’s and large dark storm petrels probably
Matsudaira’s as well
When we first observed this in 1993, I was excited about Streaked
Shearwaters because at the time they were thought to be rare in
Australian waters. This was before digital cameras, the internet,
modern pelagic field guides and of course birding-aus and I never
questioned the Hutton’s ID as they were common and seen through the wet
season although most conspicuos prior to the monsoon when the sea is
usually calm.
Another fantastic sight at this time of year coincides with the first
full moon of November. The deep sea coral and much of the benthic
biota spawns.
It produces a dense cover of what looks like an oily curry powder across
the sea This phenomenon is often misreported as oil spill. The fish,
the birds, the sea snakes and the crustaceans, everything goes mad. If
you get an oily calm night, turn on the deck lights and chase the radar
targets. You will see a spectacle that almost defies description.
The shearwater flocks are conspicuous and sometimes large. We would
locate flocks from up to 5 Nm using conventional 4 Kw marine radar. In
November many flocks would be encountered on a single voyage seen
anywhere from about 30nm WSW of fish reef to a point near Leseur Island
about 10 km south east of Cape Londonderry, anywhere the blue water occurs,
However from November, the calm seas are often interrupted by violent
tropical revolving storms with 50 knot squalls and plenty of lightening.
An exciting experience at night these storms are are short lived and
don't stir up sea conditions too much. They are definitely a spectacular
sight but when the monsoon hits, that’s a very different story with
prevailing gale force NWwinds with each surge sometimes lasting
sometimes for weeks.
In December 1998 a violent Cat 5 cyclone (Cyclone Thelma) crossed the
Boneaparte gulf and we crossed only 1 week after. The cyclone had
stirred the bottom with a force that can hardly be imagined and the
water had turned to pale milk colour. There were hundreds of dead
shearwaters of both species scattered across the sea. The depth across
much of the boneaparte is about 40 fathoms but where the track crosses
the WA/NT border it shallows for some distance. There is probably deep
sea coral here because after the cyclone, dense mats of kelp floated to
the surface and many dead shearwaters were tangled amongst it.
It is a very exciting place to be at this time of year and I wish I was
there. Congratulations on a great discovery.
Regards
Ian May
St Helens, Tasmania.
Simon Mustoe wrote:
Mike,
Thanks hugely!
Just to reiterate, I've put information about these birds up here:
http://bird-o.com/2010/10/22/is-arabian-shearwater-a-new-wintering-seabird-for-australia/.
This also includes a link to more images at
http://birdo.wildiaries.com/trips/10330.
A reminder to Aussie birders - I have until the end of this week to confirm whether the trip to see these birds will go out on the 6th November. This may be the only chance this year to see them. Call me on 0405 220830.
Regards,
Simon.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Simon Mustoe
Tel: +61 (0) 405220830 | Skype simonmustoe | Email
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From:
To: ; ;
Date: Mon, 25 Oct 2010 13:37:27 +1100
CC: ; ;
Subject: [Birding-Aus] 'ARABIAN' Shearwaters in Bonapartes Gulf - CONGRATULATIONS
Kimberley Birdwatching's annual trip to Ashmore Reef returned to Broome on
Saturday so the earliest most of us arrived home was yesterday evening with
the opportunity to view the photos of Arabian Shearwaters posted last week.
Like the Peregrine Bird Tour group we also had an exceptionally successful
trip and I will post a report later this week.
Having now seen the photographs we're gob-smacked. Those Shearwaters they
saw are something special! They are not Hutton's Shearwaters - we had
excellent views and obtained many photographs of 575 Hutton's in a variety
of plumages just three days ago. None resembled those birds. So
congratulations to Simon Mustoe, Chris Doughty and the others in that group
on their discovery. What a find!
To us they do look basically like Arabian Shearwaters and are undoubtedly
new to Australia. Moreover, they could be new to science as a separate
taxon. With so many birds together who knows, there could be a population
breeding somewhere in northern Australia or Indonesia. There are 3,000
islands in the Kimberley alone let alone the NT. That Audubon's, Tropical,
Little Shearwater group is notorious for having small populations scattered
over a wide area and there is no general consensus regarding their taxonomic
relationships. Indeed, even modern texts suggest new breeding sites await
discovery. So well done!
Mike Carter, Rohan Clarke & George Swann
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