shy v White-capped Albatross

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-seabirds-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 ============================== =============================== To unsubscribe from this mailing list, send the message: unsubscribe (in the body of the message, with no Subject line) to: birding-aus-request@vicnet.net.au http://birding-aus.org ===============================

4 comments to shy v White-capped Albatross