Robert Berry <> wrote:
Well said, Harry!
What a complex subject this is. I think we can find an excuse to
intervene in the population dynamics
( for a moment there I had a typo that rendered "poopulation", since
the topic is introduced birds like Rock Doves I was loath to correct
it).
European migrants introduced any number of birds, mammals and plants to
make themselves feel more at home or simply to improve the place. This
unleashed changes that forever change the balance between native
species and their environment. Unless we now "manage" these newcomers
(and moderate other impacts we have on the land) we can kiss goodbye to
some proportion of native species. So, perhaps, more than an excuse we
have in fact a duty to put a lid on exotic populations.
But as I heard on the radio that a program of netting Common Mynas at
their winter roosts in Sydney has begun I asked myself is this
justified ? Unless this is a sustained program the population will
simply bounce back at the end of it. In that case all that's happened
is that someone has spoiled the day for the unfortunate Mynas in the
wrong place at the wrong time. Of course, if it is sustained and
effective small hole nesting natives will benefit from increased nest
site availability and one restriction on their population size will
have been ameliorated. But what of unintended good effects of
naturalisation of exotic species ? In
the UK the introduced and very attractive Mandarin
Duck is doing well. In its homeland it's in big trouble. So what? Well,
the Songthrush, Skylark
and Chaffinch have all suffered reverses at home. All are doing well
somewhere in Australia or New Zealand.
Of the methods for interfering with nesting offered
the best clearly involves pricking (or cooking, or substituting with
dummies) the eggs because the parent then wastes a considerable time
acheiving nothing rather than simply starting again. But remember, in a
stable population the average lifetime productivity of a pair of birds
is just two more of its species. That means a lot of eggs have got to
be pricked. Planting native vegetation is a much better option.
Rob.
Please note that my email address will soon change.
I for one totally agree with Rob on planting a lot more native
vegetation but what exactly is native ? how far back do we go to
confirm native status ? what are the thoughts of all due to the now
known climatic changes that are about to take place ?????
John A. Gamblin
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