I suspect WBSWs can disperse to and colonise areas quite easily. I studied
the physiological and behavioural ecology of the WBSW for my PhD in Western
Australia in the early 1980s. I had three study sites, a coastal dune site
south of Perth, the coastal dunes at the Eyre Bird Observatory and the open
scrubland of Hamelin Station, Shark Bay. The latter site was heavily
over-grazed by sheep and feral goats (among other things) and had a very
open habitat structure, but it still provided habitat for WBWSs at very low
population densities. It's definitely very marginal habitat for the species
and I suspect it had been populated in part by individuals dispersing from
scrubbier habitat closer to the coastline and further up the peninsula. I
don't know if WBSWs still inhabit Hamelin Station, perhaps others on
Birding-aus could provide an update.
In south-eastern Australia, I've seen WBSWs in rural areas where most of the
woodland has been cleared. They are usually associated with creek lines that
weave through the landscape, especially in the Murray-Darling Basin, and
especially along creeks that have blackberry brambles. I suspect the creeks
are important highways of dispersal for scrubwrens.
I don't think it would be very difficult for WBSWs to disperse through an
urban landscape, provided that there are a few dense bushes or shrubs
(includdy shrubby weeds) adequately spaced along green corridors. The main
constraint would be the presence of predators, both native (e.g. currawongs)
and introduced (e.g. cats, rodents). I don't know if they would be excluded
from suitable habitat if there are large numbers of aggressive birds such as
Noisy Miners and Common Mynas, but I suspect they would be okay if there are
bushes or shrubs they can seek refuge in.
On the whole, WBSWs seem quite hardy animals. My research of the WA
populations showed that coastal scrubwrens can survive quite well on a salty
diet because they could tolerate high salt loadings in the body and they
had, for a bird species, well-developed kidneys. This is because strong
coastal winds carry salt spray from the ocean and deposit some of it onto
the coastal dunes, so everything gets coated with salt, including the food
that they consume. This is probably not an issue facing birds in inner
western Sydney, but I thought I'd throw that observation in just to
demonstrate the resilience of this species.
Kind regards,
Stephen
Dr Stephen Ambrose
Director
AMBROSE ECOLOGICAL SERVICES PTY LTD
m: 0402 225 481 t: 02 9808 1236 f: 02 9807 6865
PO Box 246, Ryde NSW 1680
web: www.ambecol.com.au
LinkedIn: http://au.linkedin.com/in/drstephenambrose
-----Original Message-----
From: Birding-Aus On Behalf Of
Greg and Val Clancy
Sent: Wednesday, September 6, 2017 6:43 PM
To: Charles; casliber0134
Cc: Birding-aus
Subject: Scrubwrens in inner west Sydney
It is a long way from inner Sydney but the question was posed as to the
ability of White-browed Scrubwrens to re-colonise or colonise regrowth
bushland. I have been studying the birds on Susan Island, Grafton since the
late 1970s and the first recent record of the species was made by Dominique
Potvin in November 2009 during her Silvereye research when she mist-netted
one. The nearest population to the Island, as far as I was aware, was 9-10
km to the north. Cattle had been removed from the Island in early 1997
resulting in a massive regrowth of native plants and weeds, providing cover
for birds and other fauna. The number of records of the Eastern Yellow
Robin and Tawny Grassbird increased notably after that date. A list of
fauna species of Susan Island had been published in the local newspaper in
1870 (Wilcox 1870) but the White-browed Scrubwren was not listed.
Individual White-browed Scrubwrens have been caught and banded on the Island
on 04 Sep 2011 and 28 July 2014 and there are a few other sight records to
indicate that it continues to exist there.
Regards
Greg
Dr Greg. P. Clancy
Ecologist and Birding-wildlife Guide
| PO Box 63 Coutts Crossing NSW 2460
| 02 6649 3153 | 0429 601 960
http://www.gregclancyecologistguide.com
http://gregswildliferamblings.blogspot.com.au
-----Original Message-----
From: Charles via Birding-Aus
Sent: Wednesday, September 6, 2017 4:55 PM
To: casliber0134
Cc: Birding-aus
Subject: Scrubwrens in inner west Sydney
It's lantana undergrowth at Macquarie Park.....
When the creek (Shrimptons Creek) is cleansed of weeds in coming years,
their habitat will be destroyed.
Cheers,
Charles Hunter
+61 402 907 577
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