We saw our first Western Fieldwren this weekend in the low heath north of the
Ledge Point Road, 12 km south of Lancelin. A couple of years ago we had our
first sighting of the Rufous Fieldwren at Indarra near Mullewa, 60 km east of
Geraldton. The Western Fieldwren is treated as a separate species by some
authors (e.g. HBW) but as a subspecies by HANZAB. The "Western" Fieldwren we
saw was dominantly washed out mousey grey in colour on its back, lighter below
with the heavy streaking typical of its' genus. The overall plumage colour was
a bit warmer around the rump, but no hint of rufous anywhere. Slater gives a
more accurate depiction of the bird than Simpson & Day or Pizzey & Night. The
now out of print "Fairy Wrens and Warblers of Australia" gives a good
description of the habitat and the useful note that it can be one of the most
common bird in the habitat it prefers - low heath with emergent shrubs. Besides
hearing a party of White-winged Fairy-wrens and seeing a distance Kestrel,
there were no other birds in the patch of heath we walked but we could hear
other distant Fieldwrens so on this small sample the description appears
accurate. Anyway the point of the posting is to ask others about where
precisely the line might be drawn between the two (sub)species. It has been
described as a line running from Geraldton to the FitzGerald River NP. This
bisects our observations in Lancelin and Mullewa. Unfortunately Birds
Australia's Birdata does not map Western and Rufous Fieldwrens separately (nor
are there that many records in the region of these birds). Perhaps the Atlas
forms should encourage sub-species identification. HANZAB is not particularly
helpful (most of their maps seem to be a poor interpolation of the Atlas data).
If the dividing line was known more precisely, then it might be easier to
investigate if there are gradational forms (supporting a lumping of the
species) or a sharper geographic/habitat boundary (supporting splitting the
species). It might also encourage some of us to get out and do a bit of
Atlasing in less visited areas and to stop wasting time on wild-gull chases (as
I did the previous weekend in my vain attempt at catching up with the Busselton
Franklin's Gull - BTW - has any one seen it again recently? I still have some
fuel left from the run to Lancelin and twitching pen anxious to make a new tick
now that it has completed the Atlas form. )
Also seen were at least 46 Sanderlings feeding on the wave driven piles of
seaweed on the beach opposite Edward Island in Lancelin. Never seen so many in
one spot and they are reasonably approachable.
Mark Stanley & Marieke Weerheim
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