I'm forwarding this message (which was originally sent to Richard Baxter) to
Birding Aus, at Brent's request, since he does not subscribe. There are some
quite important points about our current knowledge of this bird and its
movements that should be of interest to Birding Aus folk. And I note some
misconceptions arising in the past few days that this may help rectify. NB
he wrote this before seeing Dan Mantle's post.
Sav Saville
Wrybill Birding Tours, NZ
"Great birds, real birders"
24 Puketiro Drive
Feilding 4702
New Zealand
+64 6 323 1441
www.wrybill-tours.com
Hi Richard et al.,
As far as I'm concerned this isn't a possible! It's a for certain...
Great record and another piece in the puzzle...but as Sav has said where
that piece fits goodness only knows. You'd have to say that the chance of
finding the same NZSP 400km or so apart two days running are pretty remote.
However, the fact that this is the first (and second) record for Australia,
despite the fact that Aussies have been conscious and on the lookout for
this species for at least 6 years, would suggest this is not a regular
passage species. Roughly how many trips have been done off the NSW coast at
this time of the year in the last 6 years? And of course then there are the
trips pre-discovery where a strange stormy would have been questioned
anyway. So, I think the sooner photos of the two sightings are compared the
better, as the streaking pattern could possibly answer some questions. The
fact that the bird 'should' be heading north and was seen at Ulladulla the
following day is contrary to what would be expected, but stranger things
have happened.
The suggestion of an increase in numbers is a little bit of a red-herring I
think. I would not be comfortable suggesting that NZSP numbers are
increasing, and that this is therefore the reason for them being sighted in
Australia, or anywhere else for that matter. There is nothing that would
suggest any detectable increase in the number of NZSP we are seeing in the
Hauraki Gulf since 2003/2004, despite a lot of time spent on the water,
although this is difficult to quantify. The first trip we did into the Gulf
following Bob and Brian's Nov 2003 find was the trip on 18 Jan 2004 and we
had a maximum of 11 seen around the boat at one time. That number has not
really been markedly improved on in any trip I have done since (from
memory).
The only bird seen outside of NZ waters until this sighting was the bird
seen on 8th April just south of New Caledonia on the 2008 WPO. This is in
line with our assumption that the birds migrate north after leaving NZ
around late March/early April. Are they going north to breed or winter
though? So these sightings off the east coast of Australia to me are a
little bit of a surprise, and I would be absolutely staggered if there were
many more than a couple of records in the next 5-10 years. Of course based
on me sticking my neck out with that statement there probably will be now!
With regards to this sighted NZSP/s seen in Australia getting caught up with
migrating Wilson's I think this is unlikely. Most Wilson's heading north
are going to be doing just that I would have thought. So birds heading up
from the Antarctic now and coming past NZ would be unlikely to head west for
a thousand kms or so and then head up the east coast of Australia. I think
Wilson's are probably departing the Antarctic waters earlier than NZSP leave
NZ, so there is the possibility that they do mix (and we have seen both
species off the North of NZ in early April 2009). Wilson's were seen off
Kaikoura on 20 Mar 2009 (six birds) so they are definitely heading north
past NZ at a time when NZSP are still here. However, although we don't know
the migration patterns of either species, I'd suggest a trans-Tasman
crossing is not part of either species normal route. I'd be interested to
look at current SSTs charts to see if any fingers of warm water had snuck
across the Tasman (in either direction) possibly with warm water specialists
such as NZSP following them. On that basis, however, you would be expecting
an influx of other northern NZ breeding seabirds such as black and
Cook's/Pycroft's petrels, Buller's shearwaters, etc. Any sign of that? If
not possibly just an off course NZSP...
I'm hopeful there will be some more boats on the water over the next month
or so, and we can see if any more birds are seen. Regardless, this is a
great record and well done to the observers.
Cheers,
Brent
Brent Stephenson PhD (Ornithology)
Eco-Vista: Photography & Research + Wrybill Birding Tours, NZ - "Great
birds, real birders"
PO Box 8291, Havelock North 4157, New Zealand
Phone +64 6 877 6388 Fax +64 6 877 6300 Cell +64 274 426 638
email or
web http://www.eco-vista.com and http://www.wrybill-tours.com
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