Regarding David Geering's query/comments about Rockwarbler, I'd like to add
a couple of
points.
Firstly, with regard to range, the species is recorded far to the north of
Munghorn Gap. HBOC has breeding records from the Wingen area (lying
between Scone & Murrurundi in the upper Hunter Valley, and considerably to
the north of Munghorn Gap), and numerous other records from locations with
suitable habitat between Munghorn and Wingen. David - consult your 1994
Hunter Region bird report.
With regard to habitat, the bird is restricted to sandstone country
but not just to "Hawkesbury" sandstone. Chris Herbert, a geologist who is
a member of HBOC , has told me that there are many different sandstone
formations within the range of the Rockwarbler. For example, Narambeen
Sandstone is widely encountered.
It's always a delight to encounter Rockwarbler (usually in pairs) in the
Upper Hunter Valley and to be in their habitat. The Widden Valley, near
Wollemi National Park, is my favourite spot anywhere for birdwatching and
for its fantastic scenery.
Alan Stuart
HBOC President
----------
> From: David Geering <>
> To: ;
> Subject: Re: Origma at Capertee
> Date: Monday, 12 October 1998 13:43
>
>
> The story so far:
>
> John asked about the Origma seen in the Capertee Valley given its
> supposed restriction to Hawksbury sandstone
> I replied: The Capertee Valley is an "enclosed valley" with
> exceptionally scenic (Hawksbury) sandstone cliffs around about 90% of
> the valley. Rock Warblers are regularly seen near the escarpment with
> Glen Davis a spot often visited by birdwatchers. A lady I know has a
> house at the base of the cliffs and a pair nests each year in her
> garage. Munghorn Gap, about 85km to the north, is the excepted
northern
> limit while they also occur at Badger Ground (north of Rylstone)
> north-west of the Capertee Valley. For the distribution of NSW birds
I
> wholeheartedly recommend the book by Morris, McGill & Holmes (title
not
> at hand) put out by the NSW FOC (I think) which details range limits
of
> all NSW birds. I hope this satisfies your curiosity.
> John thanks me and remarked that he wasn't aware that Hawksbury
> Sandstone was so extensive.
> Not knowing when to leave good enough alone I replied: If we were to
be
> geologically correct I'm fairly certain the "Hawksbury" sandstone does
> not extend that far. Origma's, I think, occur on what is collectively
> known as the Sydney Basin sandstones, which is a collection of
> sandstones including Hawskbury Sandstone. Perhaps this is verging on
> the pedantic but it means that your initial question was a perfectly
> valid one.
> John replies: I see. I had wondered, given the prevalence of
sandstone
> and its associated vegetation all up the East Australian coast, why
the
> Rock Warbler, which is
> relatively common in suitable spots in the Sydney area, was so
> restricted in
> range. Your advice partly answers this, but only partly, I feel.
>
> It is time to throw open this discussion. Any birders out there with a
> better geological knowledge of the Sydney basin and the distribution of
the
> Origma than I?
>
> David Geering
>
>
|
