The dry conditions in Melbourne, and the fact that we do not water our
gardens any more, may well be the reason that Song Thrush numbers have
dropped in Melbourne.
If we think in terms of the scientific principle known as Occam's razor,
which proposes that one should shave down the accumulation of possible
explanations until the simplest reasonable explanation remains, with
regards to Song Thrush it is possible to make the following links: Song
Thrush like snails, snails like moisture, in Melbourne there is less
moisture and as a consequence there are less snails (and slugs etc).
Ipso facto, lex parsimoniae and el presto, less Song Thrush.
Tim Dolby
From: Rosemary Royle
Sent: Saturday, 17 May 2008 6:58 AM
To: Tim Dolby; birding aus;
Subject: Song Thrush: Friday Bird in Focus
There is a widely held belief that the cause of the decline in Song
Thrushes in the UK is due to them eating snails poisoned with slug
pellets. However as far as I am aware there is no evidence at all for
this - and it assumes that most Song Thrushes live in gardens which they
don't. (I am still unclear myself whether a diet of poisoned snails will
actually poison an individual Song Thrush though I am sure that the
overall effects on populations are likely to be minimal) The
intensification of agriculture together with dry spring weather,
especially in the SE is thought to be a more likely cause. They have
actually reversed their decline at the moment and are doing OK in the
wetter parts of the country.
I was interested in the remark about size of territories - which
explains why Song Thrushes are always much less common than Blackbirds.
Rosemary Royle
Wales, UK
Tim wrote:
"Snails! Song Thrush love snails! A sure fire why to track them down is
to look for empty piles of snail shells"
When I was growing up in Coburg in the 1950s, Song Thrushes were very
common and I would often watch them breaking snail shells against a rock
or the footpath prior to eating the snail. By the early 1960s, Song
Thrushes were rarely seen and my mother, who was a keen observer of
nature (and still is), said that their absence was a consequence of
eating snails poisoned with snail pellets.
How close to the mark was she?
David
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