Hi all,
The discussion about the veracity of Slaty-backed Thornbill sightings in SW
Queensland is of special
interest to me for a number of reasons - personal, philosophical and 'academic'.
Particularly as Lloyd Nielsen in his Mon, 09 Jun 2003 22:19:07 +1000 posting,
"Slaty-backed
Thornbills at Cunnamulla (W Qld)" refers to my sighting near Eulo in SW
Queensland which effectively
extended the eastern limits of the range of this species.
(ref. "Notes on Recent Sightings of Slaty-backed Thornbills in South-western
Queensland", Inglis,
Smyth, Joseph - Sunbird 22:46 - this paper summarises SW Qld records until
about 1991).)
Perhaps some additional comments may help those observers and bystanders who
may be 'struggling'
with the concept that this species may be more common in SW Queensland than has
been accepted until
now.
At this point I must emphasise that I am in no way intending to be critical or
judgemental
concerning anyone's ideas or opinions on this topic; my hope is simply to
provide another point of
view based on personal experience.
My sighting of Slaty-backed Thornbills (Acanthiza robustirostris) is mentioned
in HANZAB (Handbook
of Australian New Zealand and Antarctic Birds) Vol 6.
Unfortunately the details as provided in HANZAB are a little confused and
confusing.
The single bird sighted c. 70 km east of Windorah on 28 Sept 1984 was actual
recorded by a party
including Anita Smyth; I was not in that party and can therefore not claim that
sighting.
However, the 5-6 birds sighted 15 km east of Eulo (at the location commonly
called Eulo Bore and
more correctly known as Nine Mile Bore) on 26-27 July 1991 is my record. The
details of these two
sightings were described in the edition of the Sunbird (The Journal of the
Queensland Ornithological
Society) mentioned above.
The impression could be taken that I was accompanied by other observers at the
time of the "Eulo"
sighting but that was not the case. For that reason I would understand
completely if the claim was
considered doubtful, after all, we all from time to time have our suspicions
concerning the odd
'surprising' reports.
Not that I have ever had the impression that it was doubted.
Checking through notes from my other excursions into the SW Queensland area I
found two more records
of possible sightings of Slaty-backed Thornbills:
- 11/8/1985 between Charleville and Quilpie (a rather large area,
unfortunately, with no reference
to precise location);
- 21/8/1985 at Lk Bindegolly east of Thargomindah.
Sadly, I do not possess "total recall" so, although I can certainly remember
the trip I cannot
remember the precise details and nature of the two sightings.
At that time my experience with the birds of the region, particularly the
thornbills, was limited
but I was accompanied by a very experienced observer whose observational
abilities I did, and still
do,
respect very much.
As my notes are marked as "possible" only, we must have been aware of the
unusual nature of those
sightings.
An interesting point is that I did not list sightings of Chestnut-rumped
Thornbills during that trip
whereas a number of subsequent excursions to the same area always produced that
species.
A number of photos I took of thornbills with chestnut rumps from around Lk
Bindegolly are only of
Chestnut-rumped, A. uropygialis.
By the time of the Eulo sighting (26-27/7/1991) I had enough experience to be
able to immediately
see that these thornbills were 'different'.
I also knew that the recognized eastern extent of the Slaty-backed distribution
was around Eromanga
in far SW Qld, approx 175 km west of Eulo, by longitude.
I was and am still quite confident that the birds I was observing on that
occasion were Slaty-backed
Thornbill.
An interesting point is that I don't appear to have recorded Chestnut-rumped on
the same occasion.
Eulo is only about 50 km west of Julie McLaren's "Bowra" (located approx 1 cm
NW of Cunnamulla on
the RACQ SW Qld map, QDM6) and, as far as I am aware, is still 'mulga' country.
Therefore it would
not surprise me at all if Slaty-backed Thornbills were recorded there, however,
confirmation of
these sightings would probably mean an official eastern extension of the
accepted distribution.
Identification of Slaty-backed Thornbills can be a little difficult (from my
experience) and the
current field guides can be a little misleading.
For example, the 1997 edition of the Pizzey and Knight Field Guide to the Birds
of Australia
actually shows an illustration of an 'immature' Chestnut-rumped Thornbill with
a very dark eye,
similar to that of the Slaty-backed.
This feature is also mentioned in "Morecombe" but HANZAB seems to contradict
this.
HANZAB indicates that there is virtually nothing known about 'immature'
Chestnut-rump Thornbill but
does have descriptions of 'juveniles' which are said to have irises similar to
adult but slightly
duller. This would seem to indicate that Chestnut-rumped Thornbills in all
plumages will have
distinctly different iris colour to that of the Slaty-backed thornbill. This
should, therefore, be a
prime identification feature.
(Comment: The terms 'immature' and 'juvenile' often seem to be used rather
loosely in publications
such as field guides and illustrated bird books.)
I must admit I have often found it very hard to determine the iris colour of
many of the
thornbills I have observed; a great deal of patience and close observation is
often required to be
sure. Fortunately it is not necessary to determine the iris colour in most
cases.
Wingspan, Vol 7 No 1, March 1997, has an article on the identification of
"arid-land thornbills".
The text is very detailed but, unfortunately, this article relies on photos
only for the
illustrations which, in my view, limits
the value of the article.
Having said that, the photos in the National Photographic Index of Australian
Wildlife, "The Wrens
and Warblers of Australia", are much better for comparing Slaty-backed with
Chestnut-rumped.
The number of different observers claiming sightings of Slaty-backed Thornbill
from "Bowra" in SW
Qld should indicate that this species is more than likely there. However, to
fully satisfy some
elements of the ornithological fraternity it would be best if someone could
present a report (with
photos and witnesses) to the state and/or national "Rarities" committees.
Personally I wouldn't bother having experienced this process myself and would
be quite content to
accept my own judgement and observational skills.
But to make life easier for Julie McLaren at least some photos would be handy.
Or perhaps a visit and a sighting by one or two of the bird-watching 'elite'
would settle the issue.
In the meantime, Julie, I can readily believe that Slaty-backed Thornbills have
been observed on
your property.
Thank you for providing the facility to allow so many people to gain so much
more pleasure from
their chosen pastime.
Cheers
Bob Inglis
Woody Point
Queensland
Australia
Birding-Aus is on the Web at
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