I agree Mick,
None of the birds in that link could be confused with steadi, all have
noticeable yellow at ridge base to bill.
Cheers Jeff.
-----Original Message-----
From:
On Behalf Of Mick Roderick
Sent: Tuesday, 12 November 2013 1:50 PM
To: David James; Birding Aus
Cc: Roger McGovern
Subject: shy v White-capped Albatross
Thanks David,
The images of the birds on the link you provide still show some yellow flush
though and more than one would ever expect from a White-capped as you
suggest...so they are not ambiguous. It is those birds that have 'zero'
yellow on the base of the culminicorn that present the ID problem. I wonder
how many adult Shy's have this yellow flush during the period Aug-Oct and if
perhaps this could be used to at least make a closer judgement on an adult
Shy-type lacking any yellow observed in mid-NSW waters during that time as
being more likely a White-capped?
Your observations in your trans-Tasman travels David are relevant too.
Where does the line "...as foraging ranges of breeding birds do not appear
to overlap" (re: steadi / cauta) in Onley and Scofield stem from does anyone
know? This would be another clue that could contribute to helping get close
to an ID on adult birds at certain times of the year if the information is
reliable.
The "fresh juvenile test" seems to make a lot of sense, even if it isn't
backed up by hard science. I like Christine's suggestion of us being
'citizen scientists' out there on pelagics and I'm sure you agree to some
extent Nikolas! ;-) Of course, this is further confused by the possibility
of juvy Salvin's Albatrosses as well, which fledge at the same time as
Shy's (e.g. the candidate Salvin's off W'gong 13th Aug 2011 discussed on
SOSSA). How many juvenile birds called in the past as Salvin's may have been
juv White-capped? The discussions on the SOSSA threads show that it is not a
straight forward ID issue again and I'm not sure for how long the 'messy
leading edge' has been used as feature to pick a young Salvin's.
Mick
On Tuesday, 12 November 2013 9:11 AM, David James <>
wrote:
Nice summary of the complicated issue of identifying Shy (cauta) albatross
from Tasmania versus White-capped (steadi) albatross from Auckland
Islands at sea by Mick and Nikolas. I was looking closely at all the
Shy-types on Saturday's Sydney pelagic, trying to unravel this puzzle.
Firstly, I counted 6 different juveniles that were all White-capped in my
opinion. Chicks of Shy fledge in April whereas chicks of white-capped fledge
in August (Heather & Robertson 2000). Off Sydney we see few juvenile
shy-types until August, but in August and September we see large numbers of
fresh plumaged (i.e. newly fledged) juveniles that must be White-capped.
They are also more grey-headed on average than juvenile Shy. It is possible
to track the different White-capped and Shy cohorts as their plumage begins
to wear and moult. By October the White-capped are a little worn, but not
yet moulting. And by Nov 11th the 2013 cohort of White-capped were
moderately worn but still not moulting. On a Sydney pelagic in Oct this
year (a private charter) there were some very worn and moulting juveniles
that would be Shy rather than White-capped, but none like that in November.
The adults are more problematical as Mick and Nikolas noted already. There
were 4 adults on the Nov 11th pelagic. None of these had any trace of yellow
at the base of the upper mandible (culminicorn). Nikolas documents
that shy-types seen by him during Eagle-hawk Neck pelagics always show a
bright yellow base to the culminicorn, and he assumes that they are Shy from
the nearby Mewstone and Pedra Branca colonies, as well they may be. Nikolas
and Mick posed the question in different ways, can adult Shy from Tas lack
the yellow culmicorn base. The answer is definitely yes. My old NPIAW
"Seabirds of Australia" (Lindsey 1986) has a photos of many Shy at the
colony on Albatross Island in which I can't see any yellow, but the photo is
poor. A quick search of the internet, however, returns unambiguous photos of
Shy at the breeding grounds showing only a faint hint of yellow culminicorn
base, e.g.
http://www.anaspidesphotography-blog.com/journal/2010/2/14/tasmanian-seabird
s-field-trip-albatross-post-2.html
This indicates that the yellow base is a seasonal flush, probably at it's
height during the courtship period in Aug-Oct and already faded by December
-Jan. So of course, Shy can lack the yellow away from the breeding grounds.
But can white-capped ever show a trace of yellow? I've not seen any
evidence of this.
Adult white-capped may be slightly greyer about the face than Shy on
average, but it varies with age and individually and is seemingly not
diagnostic. Adult White-capped may have slightly more black at the base of
the primaries, but again there appears to be lots of variation and some
overlap.
White-capped is larger (longer wing and bill) by about 5% on average.
In February and March 2013 I made 6 crossings of the Tasman on cruise ship,
four of which were NZ from and to Melbourne, i.e via Bass Strait. I would
expect that in NZ waters the most numerous would be White-capped and the in
Bass Strait it would be Shy. Unfortunately, I could not see any difference
in the underwing or bill patterns either side of the Tasman (but admittedly
a big cruise ship is not ideal because I was too high off the water and
conditions were often difficult). What is more, the distribution of Shy's
was pretty much continuous across the Tasman, i.e. there was no point to
suggest a gap between the 2 ranges. BUT, there are about 75,000 pairs of
White-capped and only 5,000 pairs of Shy. This suggests that the majority of
adult birds in the mid Tasman will be White-capped and also the majority of
birds in the north-western edge of the Tasman (i.e. off NSW) will be
White-capped too.
Cheers,
David James
Sydney
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