Dear Jeff, Dick and others,
Jeff, that's an interesting observation about the pale pinkish bill. I have
to admit that it's been a long time since I studied scrubwrens over in the
west so I can't remember the colour of the bills at my three sites. However,
I've just had a look at the colour photographic prints in my original thesis
(way before the age of digital photography!) of specimens of balstoni,
maculatus and mellori that I borrowed from the West Australian Museum (n = 3
for each subspecies) and they all have pale pinkish bills. I wonder if that
is another example of suppressed melanin production, i.e. reduced
pigmentation?
Dick, if the scrubwrens of the big wet forests of the South-west also have
light blue eyes, then that does not necessarily mean the hypothesis of
suppressed melanin-stimulating hormone (MSH) production from salt-loading is
wrong. As far as I'm aware, we don't know for sure where the birds
originally came from. But there seems to be a general consensus that
Sericornis is a humid-adapted genus. If ancestral populations originated in
eastern or south-eastern Australia, and S. frontalis expanded its range
westwards along the south coast, then populations that evolved into S.
maculatus and expanded their ranges into coastal regions of south-western
Australia may have experienced high salt loads in their diets from very
early on. If there is reduced MSH secretion as a result and melanocytes in
the irides no longer produce melanins, or (in an extreme scenario) the
melanocytes have disappeared altogether because they have been
non-functional over a long evolutionary period, then it may be difficult for
populations subsequently colonising the tall, wet forests of the South-west
to reverse that situation. But if Sericornis originated in the tall, wet
forests of the South-west and radiated to more coastal habitats, then it
would be more difficult to tie the light blue eye colour to salt-loading.
Dick, I'll send you pdfs of my scrubrwen papers, as requested, in another
email later today.
Best wishes,
Stephen
Dr Stephen Ambrose
Ambrose Ecological Services Pty Ltd
m: 0402 225 481 t: 02 9808 1236
PO Box 246, Ryde NSW 1680
Facebook: https://www.facebook.com/EcologicalConsultant/
web: www.ambecol.com.au
LinkedIn: http://au.linkedin.com/in/drstephenambrose
-----Original Message-----
From: Birding-Aus On Behalf Of
Jeff Davies
Sent: Thursday, May 3, 2018 10:56 PM
To: ; 'Geoff Shannon'; 'Graeme Chapman'; 'Mike
Carter'
Cc: ; 'Stephen Ambrose'
Subject: Scrubwrens
G'day again Dick,
Yes these are just photos I have on file, I didn't do any extra Googling,
that would add many more individuals.
A broad spread of locations for maculatus, but many from tall wet forests
like Walpole, Pemberton and Busselton.
The eyes of these big wet forests birds are effectively same as those from
shorter forest and coastal heath like Cheynes Beach and dryer habitats like
Dryandra.
I think it's worth also mentioning the bill colour again since I have just
had another look through the files, the pale pinkish bill is maintained all
the way to the mangrove scrubs at StKilda SA, it's just as noticeable as eye
colour and sets the bird apart from White-browed which has a generally
darker bill.
I note that Shy and Chestnut-rumped Heathwrens also exhibit a similar
difference in bill colour.
Cheers Jeff.
-----Original Message-----
From:
Sent: Thursday, 3 May 2018 7:38 PM
To: Jeff Davies <>; 'Geoff Shannon'
<>; 'Graeme Chapman'
<>; 'Mike Carter' <>
Cc: ; 'Stephen Ambrose' <>
Subject: Scrubwrens
Jeff,
I assume the numbers you are talking about are photographs on tap in your
files?
But a good test of the Ambrose hypothesis is the source of your records of
nominate maculatus. Are any from the karri forest region which is
environmentally like the southeast Australian forests?
Cheers,
Dick
-----Original Message-----
From: Jeff Davies
Sent: Thursday, 3 May 2018 6:38 PM
To: ; 'Geoff Shannon' ; 'Graeme Chapman' ; 'Mike
Carter'
Cc: ; 'Stephen Ambrose'
Subject: Scrubwrens
G'day Dick,
37 maculatus, 5 balstoni, 8 mellori and 5 ashbyi, the eye colour is same on
all of them, pale blue.
There is a long list of things I could publish really, they crop up far too
regularly to actually sit down and write them all up formally and I still
need to focus on things that make money unfortunately.
Cheers Jeff.
-----Original Message-----
From:
Sent: Thursday, 3 May 2018 4:12 PM
To: Jeff Davies <>; 'Geoff Shannon'
<>; 'Graeme Chapman'
<>; 'Mike Carter' <>
Cc: ; 'Stephen Ambrose' <>
Subject: Scrubwrens
Of course there may be rapid colour change after death. But, Jeff, how big
is your sample size for that dogmatic statement? You should publish the
data.
Stephen, you talk about different environments in the southeast and
southwest. Most of the southwest specimens in the ANWC sample come from the
big karri forests around Pemberton, and the environment on the uplands there
is very southeastern.
I would also question your comments that Sericornis originated in New Guinea
and eventually trickled down around the east and south coast to WA. No one,
as far as I know in the phylogeographic game, thinks the Sericornithinae
arose in New Guinea. All the evidence says the opposite , that it arose in
Australia in the mid Miocene when it was still largely forested, and where
strands adapting to sclerophylly in a continent starting to desiccate
diverged into Hylacola, Calamanthus, Pyrrholaemus etc. Several lineages
dispersed later to New Guinea, which only began to rise and coalesce along
the north Australia coast till the late Miocene-Pliocene. One lineage was
the rock warbler group (Crateroscelis), with a relict surviving today in the
Sydney sandstones. Another was the cool rainforest-adapted Aethomyias group
of scrubwrens which budded off a number of species in montane New Guinea and
have little to do with Australian scrubwrens. A third group is Sericornis
sensu stricto with two species complexes. One of the complexes is the
magnirostris cluster (species magnirostris, beccarii and nouhuysi) which is
shared by Australia and New Guinea, and which could have originated in
either source. I suspect that the magnirostris complex began from a
proto-Sericornis population dispersing to New Guinea from Australia, and
speciated from subsequent to-and-fro movements across the Arafura (Torres
Strait) land bridge. The other is the white-browed frontalis group which is
endemically Australia. The simplest hypothesis is that ancestral frontalis
orginally occurred around the east and south coasts of Australia in more
sclerophyllous (but still wet) habitats than ancestral magnirostris, and has
since been broken into isolates by the Pleistocene climatic fluctuations.
These fluctuations separated the isolates in glacial episodes and rejoined
them in warmer, wetter times, driving adaptation and speciation.
I do most definitely agree with you, Stephen, that Sericornis (bot
complexes) is a humid-adapted genus, and that populations around the south
and west coasts north to Shark Bay are at the limits.
That's enough from me.
Cheers,
Dick
-----Original Message-----
From: Jeff Davies
Sent: Wednesday, 2 May 2018 11:11 AM
To: ; 'Geoff Shannon' ; 'Graeme Chapman' ; 'Mike
Carter'
Cc: ; 'Stephen Ambrose'
Subject: Scrubwrens
G'day Dick,
I wonder if there may be some sort of rapid colour change after death,
because I would agree with Graeme that photos of Scrubwrens from WA all the
way to StKilda and Port Gawler SA, along with Kangaroo Island show
consistently similar unvarying pale blue eyes.
But photos from the Lofty's match eastern birds. Speaking of soft parts it
is also worth noting bill colour, eastern "White-browed" have a noticeably
darker bill than "Spotted" which emphasizes paler pink tones, a bit like the
difference between Shy and Chestnut-rumped Heathwrens.
Cheers Jeff.
-----Original Message-----
From: Birding-Aus On Behalf Of
Sent: Tuesday, 1 May 2018 10:06 PM
To: Geoff Shannon <>; Graeme Chapman
<>; Mike Carter <>
Cc: ; Stephen Ambrose <>
Subject: Scrubwrens
Colleagues,
I have been reading the exchange of emails on scrub-wren eye colour, and
think that Stephen Ambrose's hypotheses have value. I have also just spoken
with Graeme Chapmen on the phone.
So I'll share with you all recorded iris colours on scrubwrens in the ANWC
from relevant areas:
Mt Lofty Range. Adult-plumaged males (n=7): cream (3), mid cream (2),
cream-buff, cream-ivory. Adult-plumaged females (n=5): cream (2), mid cream,
cream-buff, yellow. No juveniles.
Kangaroo Island. Adult-plumaged males (n=5): pale yellow, pale straw, straw,
pale grey-brown (probably subadult), pale cream-grey. Adult plumaged females
(n=4): pale grey (2), pale grey-brown (probably subadult), pale buff. No
juveniles.
Wet forested southwest corner of WA. Adult-plumaged males (n=7): cream (2),
creamy-white, creamy-grey, greyish cream, pale greyish cream, mid brown
(probably subadult). Adult-plumaged females (n=2): pale cream-grey (2).
Juveniles,(by plumage (n=4): creamy-white, dirty cream, mid cream, mid
creamy grey.
Shark Bay/Houtman Abrolohos: Adult-plumaged males (n=3): off-white
(Abrolhos, 1), light green (Shark Bay, 2). Adult -plumaged females (n=5):
off-white (Abrolhos, 4), light green (Shark Bay).
Now there is subjectivity of colour interpretation by different collectors
here and probable bias from dulling (darkening?) of irides between time of
collection and its recording on the specimen bench in the field. Nonetheless
it also shows that the issue is complex and that a more extensive
photographic record is needed before we can be certain of regional
differentiation in iris colour. Those photographs that are available I
accept as accurate. I also think it likely that the descriptor "grey" in
irides quoted above refer to the "blue" irides Graeme has been talking
about. These, from their photographs, I would interpret as pale bluish white
or pale blue-gray white, the same colour as the peri-orbital skin of Cacatua
triton (galerita superspecies) in New Guinea.
Cheers,
Dick
-----Original Message-----
From: Geoff Shannon
Sent: Sunday, 29 April 2018 5:09 PM
To: Graeme Chapman ; Mike Carter
Cc: ; Dr. Richard Schodde ; Stephen Ambrose
Subject: Scrubwrens
Just to add picture, male and female Tasmanian Scrub- wren April 2018.
Interesting discussion.
I am interested if anyone has good reference to the physiology /
biochemistry etc on eye colour changes. Is it just age or are there other
factors? There has been some discussion with Brown Thornbills ability to
change colour seasonally or even acute stress. I do not have references.
Thanks
Geoff Shannon
On 27/04/2018, 4:04 PM, "Birding-Aus on behalf of Graeme Chapman"
< on behalf of
> wrote:
Hello Mike,
Thank you so much for replying to my request. I'm attaching my K I image
that should have been attached to the original but was removed somehow in
birding-aus.
I'll agree, your bird's eye has a greenish tinge but it is also rather
dark and dull and in my opinion, a probable young bird.
I've been looking at the books on this one and what a can of worms! In
HANZAB you can take your pick in the text on soft parts and in the plate, it
shows maculatus with a yellow eye, which is wrong. The new CSIRO "guide"
opts out altogether on iris colour in the text and the plates are really too
small be of any use on this subject. What a pity this book wasn't published
as a concise handbook in A4 format. They obviously have all the information
but it has been compromised by shoehorning into too small a space.
What I am fairly sure about is that age is a factor here as it is with
many of our small birds - we know so little because so few of our birds have
been studied in detail.
I have a wide range of pics of this species and I'm attaching a few
examples
The first two are Brown Scrubwrens from Tasmania. The first one is an
adult male at the nest - I would describe that iris simply as yellow.
The second bird at the same nest I always assumed to be a female (on
plumage) but it has an olive coloured eye - such dull colours are usually
characteristic of younger birds and it is much more likely to be a helper
than the adult female, or if it is the female it is a younger bird. I don't
expect the sexes to have different coloured eyes as adults. This eye colour
reminds me of your K I bird.
The next pic is what I regard as a classic frontalis and I would
describe that as pale yellow - virtually all east coast birds are like this,
maybe a bit darker as you go north.
The last is the old "Buff-breasted Scrubwren" of the 1926 Checklist from
northern NSW, slightly darker yellow.
I guess what I am on about here is the difference between "Spotted" and
"unspotted" birds. All the Spotted ones I've seen have the pale blue eyes,
which gives them a totally different (to me) look.
So. how long do they take to become adult ( by eye colour )? I'd say at
least two years.
I guess I'm on the same bandwagon as my recent comments on Eastern
Whipbirds. Most of the books get that one wrong and show adults with brown
eyes, whereas in fact they are cream. How long it takes nobody knows but
it's likely to be similar to the Grey-crowned Babbler which is four years.
What really started this interest was the years I spent with Ian Rowley
studying corvids and choughs, both of which can be aged by eye colour, a
very handy indicator when you are looking at life history. We worked with
birds we banded in the nest, so we KNEW how old they were. Getting to the
Australian Raven's nests was interesting, I can't even lift a rope ladder
any more, let alone climb one.
Cheers
Graeme
Spotted Scrubwren from Kangaroo Island - eyes pale blue
>
Brown Scrubwren male at nest, eyes yellow. I assume this is an adult.
Brown Scrubwren at nest, probable immature, eyes olive.
White-browed Scrubwren, Gloucester NSW. eyes pale yellow. Virtually all
east cost birds are like this,
White-browed Scrubwren. Tooloom northern NSW subsp.laevigaster - eyes
yellow
<HR>
<BR> Birding-Aus mailing list
<BR>
<BR> To change settings or unsubscribe visit:
<BR> http://birding-aus.org/mailman/listinfo/birding-aus_birding-aus.org
</HR>
<HR>
<BR> Birding-Aus mailing list
<BR>
<BR> To change settings or unsubscribe visit:
<BR> http://birding-aus.org/mailman/listinfo/birding-aus_birding-aus.org
</HR>
<HR>
<BR> Birding-Aus mailing list
<BR>
<BR> To change settings or unsubscribe visit:
<BR> http://birding-aus.org/mailman/listinfo/birding-aus_birding-aus.org
</HR>
<HR>
<BR> Birding-Aus mailing list
<BR>
<BR> To change settings or unsubscribe visit:
<BR> http://birding-aus.org/mailman/listinfo/birding-aus_birding-aus.org
</HR>
|
