G’day all,
Recently I’ve been having some discussion about the differences between the Tasmanian Shy Albatross – T. cauta – and the New Zealand White-capped Albatross – T. steadi (or T. cauta cauta/steadi depending on your taxonomy). Various sources seem to indicate that breeding T. cauta have a yellow spot at the upper base of the beak, while T. steadi never have this yellow dot. It has also been suggested that T. steadi has black primaries 8,9,10 while on T. cauta they are black and white.
I was wondering if anybody know more about the differences, especially differences that can be identified in the field, or can confirm or deny the differences I’ve suggested? I was also wondering if anybody have photos of either species/spp. nesting at their various locations with the underwings visible (esp. P8-10)?
Cheers,
Jeremy O’Wheel ===============================
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Hi Sav,
Thanks for your comment. I agree that there is likely huge variation plus the lack of published evidence (see my comment below). This may be individual variation – as you said. However, I don’t think that it is an age-related pattern. We get both pattern types in all ages here (off Wollongong and Sydney). Onley & Scofield (2007) ‘Albatrosses, Petrels & Shearwaters of the world’ state that “foraging ranges of breeding birds do not appear to overlap” (p. 135). Do you know if that is based on evidence? I am pretty sure that steadi (with NZ bands) were re-trapped off Wollongong (I don’t know though what age the birds were and what time of the year that was – I will ask Lindsay). de Roy, Jones & Fitter (2008) ‘Albatross, their world, their ways’ erroneously swap the culminicorn field mark of the two – see chapters steadi (p. 206) and cauta (p. 208) under ‘identification’
Cheers,
Nikolas
Hey Jeremy & all, The bill spot is fine but only a discriminator when it is present, of course. The wingtips of birds here in NZ (and we see hundreds – maybe thousands – each year) are hugely variable. It might just be an individual variation thing, and I’m much more inclined to believe that, or that the variation is due to age than subspecific difference – otherwise we are getting heaps of cauta here (and that wouldn’t seem to be very likely………). Happy to be proved wrong, but would need some convincing argument.
Cheers
Sav Saville Wrybill Birding Tours,NZ “Great Birds, Real Birders” http://www.wrybill-tours.com sav@wrybill-tours.com +64 27 680 3740
Ok cool. I only had 2 photos of birds that I could be confident were T. steadi (because they were breeding at Auckland Island) – so it’s probably good to note that limitation with my assessment (Thanks to Bill Abbott for the photos!). I have some vague plans of visiting the breeding islands for both species at some point in the next few years, so if that happens, or if anybody else is visiting either, it would be great to get a large number of photos of many birds to do a more robust comparison.
Thanks,
Jeremy
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Hi Jeremy & Jeff,
Me to. In addition to the primary patterns of both adult and young birds, I would also be very interested in the head and neck colour of the fledglings of each taxon.
Cheers,
Nikolas
G’day Jeremy,
I would be very keen to see any photos you get and to swap notes on this subject.
Cheers Jeff.
Sent: Wednesday, 27 June 2012 12:06 PM Cc: Nikolas Haass; birding-aus
Ok cool. I only had 2 photos of birds that I could be confident were T. steadi (because they were breeding at Auckland Island) – so it’s probably good to note that limitation with my assessment (Thanks to Bill Abbott for the photos!). I have some vague plans of visiting the breeding islands for both species at some point in the next few years, so if that happens, or if anybody else is visiting either, it would be great to get a large number of photos of many birds to do a more robust comparison.
Thanks,
Jeremy
On Wed, Jun 27, 2012 at 11:58 AM, Jeff Davies wrote:
Nikolas is correct,
when the outer most primary is without a white inner web and entirely dark it shows up best in flight as a right angled step. But I can find no evidence that it is exclusively a steadi feature or that they always show it. Would have been handy if it worked but the feature doesn’t work as far as I can tell.
Cheers Jeff.
Sent: Wednesday, 27 June 2012 9:31 AM Cc: birding-aus
Hi Jeremy, Jeff et al.,
I second the point about the yellow base of the culminicorn in cauta.
I also use the underprimary pattern – i.e. the ‘step’ in p8-p10 caused by more solid dark grey on both webs – to ID a ‘possible steadi’, as opposed to the throughout ‘comb’-patterned underprimaries for a ‘possible cauta’ (caused by dark grey outer webs and white inner webs). However, there seems to be much variation and there seems to be no robust evidence at all at this point (to my knowledge there is still nor peer-reviewed paper on this field mark).
I disagree that this pattern is more obvious when the wing is spread. I think the opposite: When the wing is ‘overly’ spread all primaries appear bicoloured – even in a Salvin’s Albatross, which normally should have a solid dark wingtip (caused by all grey visible undersides of the primaries).
Cheers,
Nikolas
Nikolas is correct,
when the outer most primary is without a white inner web and entirely dark it shows up best in flight as a right angled step. But I can find no evidence that it is exclusively a steadi feature or that they always show it. Would have been handy if it worked but the feature doesn’t work as far as I can tell.
Cheers Jeff.
Sent: Wednesday, 27 June 2012 9:31 AM Cc: birding-aus
Hi Jeremy, Jeff et al.,
I second the point about the yellow base of the culminicorn in cauta.
I also use the underprimary pattern – i.e. the ‘step’ in p8-p10 caused by more solid dark grey on both webs – to ID a ‘possible steadi’, as opposed to the throughout ‘comb’-patterned underprimaries for a ‘possible cauta’ (caused by dark grey outer webs and white inner webs). However, there seems to be much variation and there seems to be no robust evidence at all at this point (to my knowledge there is still nor peer-reviewed paper on this field mark).
I disagree that this pattern is more obvious when the wing is spread. I think the opposite: When the wing is ‘overly’ spread all primaries appear bicoloured – even in a Salvin’s Albatross, which normally should have a solid dark wingtip (caused by all grey visible undersides of the primaries).
Cheers,
Nikolas
Hi Jeremy, Jeff et al.,
I second the point about the yellow base of the culminicorn in cauta.
I also use the underprimary pattern – i.e. the ‘step’ in p8-p10 caused by more solid dark grey on both webs – to ID a ‘possible steadi’, as opposed to the throughout ‘comb’-patterned underprimaries for a ‘possible cauta’ (caused by dark grey outer webs and white inner webs). However, there seems to be much variation and there seems to be no robust evidence at all at this point (to my knowledge there is still nor peer-reviewed paper on this field mark). I disagree that this pattern is more obvious when the wing is spread. I think the opposite: When the wing is ‘overly’ spread all primaries appear bicoloured – even in a Salvin’s Albatross, which normally should have a solid dark wingtip (caused by all grey visible undersides of the primaries).
Cheers,
Nikolas
Thanks everyone for replies, especially those that sent photos – they were very helpful.
My opinion, which is admittedly still based on very limited evidence is this;
T. cauta (Tasmanian Shy) has a yellow dot at the base of its beak when breeding (or at some point during its life), but doesn’t always have this – so if you see a bird with this mark, I’d be happy to call it T. cauta, but if it doesn’t have it, it still could be.
T. steadi never has the yellow dot, but does have black leading underwing primaries (probably P8-10) – however the colour of the other primaries in both species does vary a bit, so you can get birds with those 3 primaries black, and the rest white, or you can get ones where the difference between those 3 and the others is almost negligible – however if they’re black, it’s T. steadi. It’s also more difficult to spot this difference with birds in flight, than when they spread their feathers a little landing and taking off. So ideally, to separate the species when they don’t have a yellow dot, you need a high quality photo of the underside of the primaries landing or taking off.
However, I should add that this conclusion is based on very few photos, and one stuffed bird, (as well as some anecdotes), so I’m definitely open to more robust evidence.
regards,
Jeremy O’Wheel
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G’day Jeremy,
I have also been looking at the under-wing issue between these two for the last couple of years and have found equal variation of blackness in the under-primaries for both. The bill colour seems to be a good feature however. I will look closer at these two birds next year but would be very interested to hear any other insights into this pair you may uncover yourself.
Cheers Jeff.