Hello John
A-chloralose is an anaesthetic agent. It basically stupifies or sedates the
birds, which can then be collected and dealt with further. In the case of the
gulls, this probably entails humane destruction.
The technique has been widely used for bird control here and elsewhere, though I
have heard of opposition to its use in controlling feral pigeon populations in
city centres. The use of dosed bread should be reasonably specific to the gulls,
perhaps mainly because they are likely to out-compete other possible scavengers.
The good thing about this technique is that you have the option of keeping
unintended 'casualties' alive until they recover from the effects of the drug,
thus minimising non-target impact. Of course, if non-target mortality is not an
issue (i.e.no other species likely to take the bread bait, or only insignificant
numbers) then the dose in the baits could be at lethal levels. This would save a
step in the process, but I honestly don't know what the ethical stance on this
is. Certainly, there are legal restrictions, and ethical guidelines, on the use
of poisons. These will vary from State to State. Perhaps others might be able to
comment on that aspect.
This technique would be much more cost-effective (i.e. birds taken per unit
effort) than shooting, netting or other techniques. I doubt that anyone relishes
the thought of going out and killing thousands of gulls. It's just a fact that
human influences on the natural world have reached the level where we often have
to actively manage 'natural' processes like gull predation. Silver gull numbers
have boomed as a result of our provision of more food sources, hence their
impact on other bird populations now exceeds 'natural' levels. Letting nature
take its course is no longer an option if we want to have Banded Stilts into the
future.
John Nankervis wrote:
> I have recently read with interest a copy of Galah No. 44 the inhouse
> newsletter of Birds Australia concerning the desecration of the Banded Stilt
> breeding colonies by Silver Gulls at Lake Eyre. In the report it makes
> mention of action that could be taken to control the predation by the gulls
> should there be any further breeding by the stilts.
>
> I quote: "Proven methods exist for gull control, including the use of bread
> soaked in alpha-chloralose. This has proved effective in extensive gull
> control programs carried out in Western Europe and North America over the
> last 30 years."
>
> I am all for adopting ways to stop the predation but my question is this,
> what specific effect or deterrent does "alpha chloralose" have on the gulls?
>
> Can anyone throw some light on this for me?
>
> John Nankervis
> Barham N.S.W
>
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+----------------------------------------+
Richard Johnson
Roma District
Tel: (07) 4622 4266 Fax: (07) 46 22 4151
E-mail:
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