G'day nature lovers.
After the chatter here on Birding-Aus re House Sparrows, I contacted a
number of lists across the world. Here's my take on it which I circulated to a
list in the USA. . .
Thanks to everyone who responded to my House
Sparrow querie.
Every part of the developed world that I write to
reports the same thing - a big decline in House Sparrows. They are temporarily
increasing in Scotland and Wales in the United Kingdom, but crashing on the east
coast of that country. Generall, the pattern is the same: First they vanish in
the cities, then the suburbs and then around country towns and finally down on
the farm.
A recent exhaustive study in Britain indicated that House Sparrows
tend to raise two clutches in a season; one as a back-up. The parents primarily
provision their young with insects whilst in the nest. It appears that insects
are vanishing at that critical time when the second clutch is being raised and
the young are rarely surviving. The author of the study felt that this is
behind the gradual decline. I'm not sure if this can explain such a
universal decline or the pattern of declines, but it may be an area which
requires further examination.
Perhaps the House Sparrow will bounce back. Perhaps those with
behavioural/physical character traits which overcome their current difficulties
will emerge and we'll have a new breed of Super House Sparrows (Passer
domesticus giganteus) to contend with. Time will tell.
Meanwhile, it has to be a concern that a small generalist
granivorous/insectivorous bird with an incredibly successful past is
declining comparatively rapidly, fairly uniformly and in the same pattern all
over the world. Many would like to celebrate the disappearance of what is a
feral species in Australia and the US (I'm told that they're actually feral in
Great Britain too - supposedly brought in by the Romans). However, this
celebration has to be tempered by the fact that a bird like this can be
disappearing when we don't know the cause . . . a bird which appears to
share much the same sort of characteristics as many of our own native species
here in Australia and the US too.
We are no doubt all aware that our environment is
under threat from a number of quarters, but an almost universal decline of
a species like House Sparrows confirms what I and probably most nature
lovers and conservationists are beginning to suspect: that there may
be something subtle, fundamental and very far reaching going very
wrong in our world and the tip of the iceberg is a small brown, vanishing
bird.
Happy Birding (anyway)
Ricki Coughlan
Sydney, Australia
