small forests, small birds?

Subject: small forests, small birds?
From: "David Geering"<>
Date: Mon, 17 Aug 1998 13:33:31 +1000
 Can you tell me, where are the small birds in the box-ironbark forests.
> has been suggested that the 1984 drought saw a marked decline in some
> populations and then the 1994 drought resulted in some further local
> extinctions.  A sorry tale of a severely fragmented habitat if this is
> case.
Russell Woodford replied:
All these suggestions sound likely - but populations do tend to recover IF
the habitat is suitable.  That's what we're losing.  Also, many of the
birds in this sort of forest migrate or are nomadic, relying on similar
forest in other places - and THAT's where we are getting into trouble with
habitat loss.  And finally, there's always BAD LUCK - going to a 'certain'
place for a species and dipping.  I haven't found a solution to that
myself either.  Perhaps more trips is the only solution!!

Agreed that habitat loss is a major factor.  Dipping out could also be the
case but I covered a hell of a lot of ground over three days and the story
was repeated at most locations.  I can't be THAT unlucky.  The small
resident species -such as Thornbills, Weebills, Fairy-wrens, Speckled
Warblers etc.  were the birds that were often missing.  I did see small
numbers of these species at some locations but they were missing from many
others where they would be reasonably expected.

I suggest that local extinctions due to severe drought, for example, are
compounded by the isolated nature, and small size, of many box-ironbark
remnants.  They can't be re-colonised because they are simply to far from
other patches and aren't connected.  This doesn't, however, explain why
some of the larger forests had few small birds.  A long history of grazing
(= loss of understorey) and burning perhaps, or were these areas so heavily
managed for timber harvesting in order to produce an even aged stand that
the loss in structural diversity has resulted in a loss of biodiversity.

Either way, we've really stuffed up the box-ironbark forests.  This brings
us back to a thread that was operating several weeks ago (and I don't
really want to resurect it).  These habitats need to be repaired if we are
to avoid further losses.

David Geering

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