To: <>, "'Jeff Davies'" <>, "'Geoff Shannon'" <>, "'Graeme Chapman'" <>, "'Mike Carter'" <>
Subject: Scrubwrens
From: "Stephen Ambrose" <>
Date: Thu, 3 May 2018 17:40:17 +1000
Hi Dick,

Thanks for your feedback, much appreciated. Yes, scrubwrens are abundant in
the tall forests of the South-west, and I agree with you that those habitats
would have similar environmental conditions to those in the south-east. My
research in the 1980s (PhD at the University of WA) was not on those
populations, it focussed entirely on the physiological and behavioural
ecology of populations that were in coastal sand dunes (Rockingham and Eyre)
and in scattered shrubland (Hamelin Station, Shark Bay): 

1. Rockingham (approx. 45 km S of Perth) - mesic or temperate environment of
the South-west (coastal dunes); Ave annual rainfall = 702 mm
2. Eyre Bird Observatory on the coastline of the Great Australian Bight -
semi-arid environment (coastal dune/mallee woodland ecotone); Ave annual
rainfall = 317 mm
3. Hamelin Station, Shark Bay - arid environment (scattered shrubland
dominated by Acacia and Atriplex species). Ave annual rainfall = 204 mm

The physiological (water & electrolyte metabolism, basal metabolic rates)
and behavioural ecologies of scrubwrens were very different at each site and
reflected responses to the local environmental conditions. I'm sure that if
the same studies were conducted in the Karri forests of the South-west,
there would be quite different results yet again. So when I say that I
studied scrubwrens in marginal environments,  I believe that they were
marginal, not only in terms of the distribution of scrubwrens in Australia,
but also in terms of the distribution of scrubwrens in the south-west of WA.
That marginality can be expressed in terms of low rainfall and humidity,
high ambient temperatures in summer, salt loading of their diets, ground
reflectivity of sunlight, openness of habitats, and possibly greater
competition for limited resources.

For your interest, the titles of the papers from that study are listed

Ambrose, S. J. (1984). The response of small birds to extreme heat. Emu. 84:

Ambrose, S.J. (1985). White-browed Scrubwren Sericornis frontalis research
at Eyre. Eyre Bird Observatory Report No. 3, 1981-83. Pp. 84-93  (Royal
Australasian Ornithologists Union, Melbourne).

Ambrose, S.J. & Bradshaw, S.D. (1988). Seasonal changes in standard
metabolic rates in the White-browed Scrubwren, Sericornis frontalis
(Acanthizidae) from arid, semi-arid and mesic environments. Comp. Biochem.
Physiol. 89A: 79-83.

Ambrose, S. J. & Bradshaw, S. D. (1988). The water and electrolyte
metabolism of captive and free-ranging white-browed scrubwrens Sericornis
frontalis (Acanthizidae) in arid, semi-arid and mesic environments. Aust J.
Zool. 36: 29-51.

Ambrose, S.J. & Bradshaw, S.D. (1988). Water and sodium turnover in
White-browed Scrubwrens Sericornis frontalis (Acanthizidae). Proc. XIX Int.
Orn. Congress, Ottawa, Canada. Pp. 1506-10.

Ambrose, S.J. & Davies, S.J.J.F. (1989). The social organisation of the
White-browed Scrubwren Sericornis frontalis Gould (Acanthizidae) in arid,
semi-arid and mesic environments of Western Australia. Emu. 89: 40-46.

I'm happy to send you copies of those papers if interested. In more recent
years, Rob Magrath's research group at the Australian National Uni has
studied the behavioural ecology of White-browed Scrubrwens in Canberra, and
its results are quite different to what we found in scrubwren populations at
my sites in the south-west of WA and what Belinda Brooker found in her PhD
study at Shark Bay in the late 1980s (Murdoch University). I think this
demonstrates that care must be taken in extrapolating the findings of
studies of a species in one type of environment to also apply to that same
species in other environments.  Although it would now seem as if we are now
referring to two different species (the Spotted Scrubwren and White-browed
Scrubwren), which makes a lot of sense to me based on what we know of the
two taxa.

I accept your explanation of scrubwrens colonising PNG from Australia,
rather than the other way around. In fact, my initial remark yesterday was
rather flippant (apologies for that) and I corrected myself in an email to
Birding-aus late yesterday afternoon (see attachment).

Anyway, all this discussion about scrubwrens has definitely renewed my
interest in them (not that it really went away) and I would definitely like
to research them again if and when the opportunity arises. 


Stephen Ambrose
Ryde NSW   

-----Original Message-----
Sent: Thursday, May 3, 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 

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.



-----Original Message----- 
From: Jeff Davies
Sent: Wednesday, 2 May 2018 11:11 AM
To:  ; 'Geoff Shannon' ; 'Graeme Chapman' ; 'Mike 
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


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

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.



-----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.

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

    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

    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.



    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

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