Apologies - tried to send this earlier including BA, but it didn't go,
hopefully it will this time.
Regards,
Allan
>
> Hi David,
>
> Firstly I must apologise to most BA posters - if there is too much
> nitty-gritty in this email. However, the mailing list of BA is very broad and
> the chance of it reaching someone with breeding ground experience of these
> birds, or being forwarded to those who do, is far greater if I send it to the
> list than not. There are images associated with this post that will not reach
> you if you receive this email via BA, so if you are interested contact me off
> line and I will forward an illustrated copy to you.
>
> We've been trying to get a handle on the Shy/White-capped dynamic in our neck
> of the woods for a while.
>
> We agree with timing of wing moult characteristics of juvenile birds that
> you've presented below and that is why we've considered most of our birds off
> Newcastle/Port Stephens at this time of year to be steadi. From the data
> collected on by-catch birds, there appears to be much evidence that cauta do
> not wander too far north in the Tasman, which appears to be in complete
> contrast to steadi. I think the call on cauta was suggested, due to the
> relatively white forehead and cap on such a young bird, despite the clean
> wing.
>
> The other interesting thing is this culminicorn flush - there has been some
> suggestion that it might be a breeding ground flush, although you mention
> that this could be a year round feature (we'd love to confirm this as you
> allude to) - a bird off California clearly exhibiting this feature seems to
> suggest that it could be a year round feature.
>
> However, we heard a suggestion lately, that a young Salvin's seen off
> california showing a strong orange bill base (apparently advanced beyond it's
> other age indicators), may have been due to it being subject to hormonal
> responses to a longer day period in the northern summer - and I wonder if
> the California Shy could be in the same hormonal response boat, so to speak.
> It may be that the yellow culminicorn base is a seasonal flush on cauta, see
> below.
>
> One of the problems separating adults, is I have seen a couple of (apparent)
> steadi with the yellow bill base feature, one from the forty fours in the
> Chatham Islands (second to last photo from nzbirdsonline below) and a bird
> off the Auckland Islands in a skirmish in the last photo (making things a
> little frustrating from trying to find a totally reliable feature).
>
> http://nzbirdsonline.org.nz/species/white-capped-mollymawk
>
> Although the flush is not strong the forty fours' bird is also missing the
> dark spot on the mandibular unguis that is usually associated with steadi,
> contrastingly it shows a generally clean yellow bill tip which is more
> generally a feature of adult cauta. Further, although this bird is obviously
> in its breeding cycle it doesn't have a strong yellow background colour to
> its bill. All the birds in the skirmish appear to have yellow hued bills, as
> well (more than a little frustrating - although this may be perhaps due to
> colour cast in the images?).
>
> Whether there is a small number of NZ breeding cauta I can't say, but if not,
> these birds certainly seem to be reason to suspect some overlap, although how
> much would be difficult for us to pin down. The lack of the yellow base in
> steadi seems to be true on birds at South West Cape in the Auckland Islands,
> also featured in the accompanying photos on the nzbirds site.
>
> Anyway, I've been noticing that cauta in Tasmania waters generally have a
> noticeable yellow background colour to the bill, which is mentioned by
> Shirihai (see Raja Stephenson's excellent collection of photographs here -
> http://www.adarman.com/Pelagics/Tasmania-Pelagics ). This is in contrast to
> the blue-grey background colour of steadi.
>
> We had a bird last November off Port Stephens that appeared to have a yellow
> background colour to the bill although it does not have the yellow base to
> the culminicorn, and it isn't the first time.
>
> I ran a little test on this November 13 bird, and two other birds from a
> previous year; another yellowish billed bird from and another that had a
> blue-grey bill from the same day (although due to the lack of a yellow
> culminicorn base we thought all would be steadi). By over-saturating the
> photographs the background colour of each bird's bill should be emphasised.
> The November bird's bill came up very yellow the blue-grey bird relatively
> unchanged and a third bird seen on the same day as the blue-grey billed bird,
> came up yellow as well (even appearing more yellow at the base of the
> culminicorn).
>
> Have a look at the comparisons below - although I don't think we can make
> anything concrete out of it until we have some banding data to back it up,
> there certainly seams to be a difference in bill background colour that could
> be a distinguishing factor (as Shirihai claims). Raja's Tasmanian photos
> appear to back this theory up - except of course for the culminicorn base.
>
> The first and third birds certainly seem to have cauta coloured bills when
> the colour is exaggerated, but the second example doesn't - however, such a
> circumstance would suggest that cauta does not always have the yellow at the
> base of the culminicorn away from the breeding grounds.
>
> Looking at the birds below it is easy to see how a seasonal flush could make
> a yellow bill base come to the fore, while the same hormonal response in
> steadi would show only a little yellowing if any at all.
>
> More information is clearly needed....or am I drawing a very long
> hypothetical bow?
>
> Regards,
>
> Allan
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> On 19/08/2014, at 12:25 PM, David James via Birding-Aus wrote:
>
>> Hi Mick,
>>
>> Thanks for your Port Stephens Pelagic 10 August
>> trip report on the SOSSA website.
>> http://www.sossa-international.org/forum/content.php?699
>>
>> The photos of the Shy type albatross are very
>> interesting. In the text you wrote it was first thought to be a
>> candidate Salvin's but is now "considered to be a Shy-type
>> (most likely a cauta) with very dark primaries".
>>
>> I agree this is not a Salvin's because the head and
>> mantle are not grey enough and the there is too much contrast in the bill
>> pattern. I would say it is not a cauta either but almost certainly a
>> steadi (or White-capped Albatross) the NZ subspecies of Shy that breeds on
>> the Auckland Islands. The main ID feature is the fresh juvenile plumage at
>> this
>> time of year. Tasmanian Shy Albatross (cauta) fledge in April, and by
>> August they are showing signs of wear and moult. Conversely, steadi fledge in
>> August and arrive off the NSW coast immediately. Quite a few
>> juvenile steadi have dark underside to the primaries like this,
>> but I'm not sure that cauta ever shows such dark primaries.
>>
>> Over the last few years steadi juveniles have been
>> much more common than cauta juveniles on Sydney pelagic and Halicat
>> whalewatching trips. Until August, most shy-types are adults,
>> whilst juveniles (which must be cauta) are rare, and older immatures are
>> even rarer. from August onwards fresh juveniles outnumber worn juveniles by
>> maybe 3 or 4 to 1.
>>
>> Just about all the adults off Sydney might be
>> steadi . For a couple of years I've been looking for an adult with a yellow
>> flush at the base of the culminicorn, but haven't seen one. It seems
>> this character is diagnostic of cauta and never occurs in steadi. I
>> understand that in Tasmanian seas the presumed cauta show this year-round,
>> although I haven’t been down that way in about 2 decades. Unless
>> cauta can lose that yellow flush when they leave the breeding seas, nearly
>> all
>> the adults off Sydney must be steadi.
>>
>>
>> Cheers,
>> David James
>> Sydney
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