John Leonard's question has opened up a very interesting discussion.
For what it's worth, here are some observations of my own.
I know the forest mentioned by Terry Pacey very well, being a frequent
visitor when I lived in Gatton (it's a small world Terry - I'm surprised
we never crossed paths). Though Variegated, Superb and Red-backed FW's
could all be seen in a very small area, it was my impression that the RB's
were always in grassy open forest, particularly that thinned by selective
logging, while Var's and Superbs were usually in shrubby forest. How the
latter two spp partitioned habitat was much less apparent. On one occasion
at this site I watched these two spp in a loose flock foraging together
on fallen shrubs and small trees beside a newly-cleared track. I can only
assume that in this case, some resource partitioning at a much less observable
scale was in effect e.g. feeding on different invertebrates. My feeling
generally though is that Var's were more 'interior' birds and the Superbs
were 'edge' birds. The Var's were typically in the shrubby gullies inside
the forest and Superbs in more open, though shrubby, areas at the edges.
This seems borne out by observations elsewhere in SE Qld but is by no means
an iron-clad rule. I have certainly seen Var's on ecotones e.g. between
dense riparian vegetation and more open adjoining forest types, including
quite disturbed areas . The idea of Superbs as an edge species would fit
in with their ability to adapt to suburban gardens. These observations
seem to fit in well with those of Andy Burton (Superbs in disturbed, weedy
areas) and Sean Pywell (Var's in the interior of mallee patches, Superbs
on the edges).
The above comments only apply to the nominate lamberti in SE
Qld. Out here at Roma, some 450km WNW of Brisbane, We have Var's, presumed
but not confirmed assimilis, Superbs and White-winged. It is possible
to see all three in close proximity but the WW's are always in open grassy/chenopod
areas. They only overlap with Superbs and Var's where taller shrubs encroach
into grassy/chenopod herblands. The Superbs and Var's are often in the
same habitat together here (generally brigalow regrowth and shrubby poplar
box woodland, sometimes with the introduced shrub African boxthorn) with
no obvious partitioning. It is notable that the Superbs are in urban areas
(parks and gardens) of Roma but the Var's never are. As an aside, both
species seem to love African boxthorn, which tends to invade cleared areas
on alluvial soils here at Roma.
Assimilis appears adapted to much more open habitats than the
other races. They are present in the mitchell grass downs of central and
northern inland Qld, occurring with WWFW's in part of this area, and I
have seen a mixed party of assimilis and Red-backed FW's in a gully
covered by spinifex and sparse low trees at Lawn Hill. Yet more possibilities
for research on resource partitioning by fairy-wrens!
Has anyone interested in this topic got access to Rowley and Russell's
monograph on the fairy-wrens? There might be some illuminating information
in there if they could share it with the rest of us.
A final thought. This line of discussion might prove useful to the
editors of HANZAB 5 - Hugo Phillipps, are you reading this???
Senior Conservation Officer, Habitat Case Studies
Tel: (07) 4622 4266 Fax: (07) 4622 4151