|
I thought the recent Birds
in Backyards project from 2004 (2003?) showed Noisy Miners were more aggressive
and inhibitory to other birds speices (i.e. more NM=less others), whereas Indian
Mynahs there was no correlation.
I am trying to think what
there are more of than 25 years ago in Sydney - definitely Pied Currawongs,
wattlebirds, and now Grey Butcerbirds - do we think there are more Noisies as
well?
Cas
G'day nature lovers
I'm not aware of any studies on this, but the
increase in Pied Currawongs in recent decades may well be placing the
same sort of pressure on sparrow popuations in urban Sydney as Collared
Sparrowhawks may be doing in the ACT. However, we should consider too that
sparrowhawks are present in a number of country towns across Australia and many
of those towns are now strongholds for our little brown feral friends.
The spread of Indian Mynahs, which compete for
similar nesting and food resources, may play a part in falling numbers of
sparrows. The same may be true of European Starlings which also appear to be
declining in areas of urban Sydney which are favoured by the Indian Mynah. I
have noted that the starlings are still also quite abundant in those
country areas where Indian Mynahs are not yet present too.
Somebody cited the recent study in the UK which
demonstrated insect declines during critical breeding stages for the House
Sparrow. This may be the cause of the House Sparrow's decline in the UK but it
may not be the same cause here (that's not to say that it may be too, as we
have no studies on this in Australia and who bothers to study declines
in feral birds here?).
It's my personal guess that birds such as Pied
Currawongs are painted as big bogeymen of many small bird species without
sufficient justification or research into all the factors for their
declines in urban habitats. The same could well be true for Indian Mynahs (but
the presence-absence thing is causing me to do a little finger pointing in this
instance). However, there could me many subtle elements at play here and
conjecture will do little to clear these matters up without proper
research.
I find myself oddly pleased when I see
excellent numbers of feral House Sparrows in our country towns these days. Apart
from the fact that they are a delightful and fascinating species, it's good to
know that we are keeping them alive in case they become extinct in the UK.
Perhaps one day we can return thousands of these charming chappies to
Europe once they have resolved whatever issues it was which caused that
possible extinction. Imagine the utter rapture of our friends
from England were we to help them to bring the House Sparrow
back! Meanwhile, I feel that we should jelously and carefully guard these
precious little fellows in what has become (whether we like it or not) our
great southern Noah's Ark.
Happy birding
Ricki Coughlan
Sydney, Australia
| 