Hi Folks
I've enjoyed reading the ongoing discussion on the perceived bustard
decline. Here are a few random thoughts that arise in my tiny little
mind as a result:
Traditional Hunting: it doesn't matter whether you kill bustards with
spears, rifles or laser-guided artillery, they are just as dead. The
important thing is the rate at which you kill them.The question of
allowing continued traditional harvests gets bogged down on the choice
of hardware, when the real issue is how much to take. I support trad use
but believe that trad users have a responsibility to look beyond their
needs to the wider picture. Just saying 'it's not my fault that the
bustard (or whatever) is declining, I want my share' isn't good enough
in this changed world. Anyone interested in this topic might like to
look up what Aboriginal communities on Cape York are doing with managing
their harvests of dugong.
Illegal hunting: goes on but no-one knows, for obvious reasons, to what
extent. A story that came to me indirectly maybe 20 years ago
demonstrated that impacts can be severe in a local area. I was told that
a railways gang working in western Qld had shot 600 bustards during the
several months they were working in the area. I have no idea how
reliable that figure is but it probably wasn't way off the mark. It's
probably an exceptional example but I'm sure a certain level of hunting
goes on. A lot of people travel the roads of the north these days, on
top of the generally sparse permanent population, and bustards are an
easy mark for anyone who wants one (or more!). It is completely beyond
the means of any enforcement body to prevent such hunting.
Any legalised hunting regime will have to take into account both the
ecology of the bird (a K-species with low recruitment) and the fact that
it will be imposed over a unknown and uncontrollable level of illegal
hunting, plus any other identified threats. I personally can't imagine
anything over a very low level of hunting being sustainable.
Habitat change: I think it was Andrew Stafford who commented on their
ability to 'hang on' in settled areas of central Qld. I'd go a bit
further. Bustards are actually colonising new habitat (pasture and
cropland) where they were formerly unknown. I don't offer this as
justification for largescale tree-clearing, just as an illustration of
the complexity of responses to habitat change. It's worth noting that
invasion of grasslands by woody weeds is thought to be a cause of local
decline in the NT. My own experience with prickly acacia in the Mitchell
Grass Downs (MGD) supports this. Here we have a loss of habitat due to
changed fire regimes and/or introduction of exotic plants. These are
potentially severe threats operating at a landscape-wide scale. For
example, prickly acacia currently infests about 7 million ha. of the 23
million ha. MGD.
Foxes: the 'Action Plan for Australian Birds 2000' lists foxes as a
probable cause of decline, noting that the area of greatest decline
coincides with highest fox abundance. My own experience suggests this is
so. Bustards still occur where there are foxes but as far as I can tell,
most breeding here in western Qld occurs north of the dingo fence. Foxes
are very common south of the fence and it seems more than coincidence
that bustards are less common, and bush stone-curlews and squatter
pigeons virtually absent, in this area. All three birds are much more
common in 'dingo country'. What's the connection? I've never seen a
scientific study, but the amassed observational evidence over a wide
area indicates that dingoes actively suppress foxes. I speculate that
dingoes hunting in packs and selectively targeting high-return prey like
'roos are less of a predator of ground-nesting birds than is the
solitary fox that takes any opportunity that presents itself. So, where
dingoes dominate, predation on birds is lessened. Of course, woolgrowers
are unlikely to be keen on pulling down the fence! But other forms of
fox control may be just as, or even more, useful. For instance, foxes
are easily baited and very sensitive to 1080. There may be a threshold
level for fox numbers, hence predation levels, since foxes are present
in the MGD but this remains a bustard stronghold.
Grazing: in my experience, it seems that sustainable grazing, by cattle
and sheep, is compatible with persistence of bustards. This applies
across a variety of native pasture types, it may not apply to exotic
pasture. Overgrazing, on the other hand is no good for anything.
A decline?: Rory's Atlas figures look convincing but I'd feel happier if
we were comparing like with like as far as methods go. We've argued
about this before in this discussion group and I am still not convinced
that the new point-location based techniques can be directly compared
with the older, 'tick off the ten minute square' technique.
That said, there seems no doubt that bustards have declined, and
continue to decline, in the south of the country. I don't think this is
the case in the north, except in localized areas. But because the
grasslands and savannas of Northern Australia seem to hold good numbers
currently is no reason for complacency.
Richard
--
+----------------------------------------+
Richard Johnson
Habitat Case Studies Project Officer
Qld Parks & Wildlife Service
Southwest District
Tel: (07) 4622 4266 Fax: (07) 46 22 4151
E-mail:
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