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I can't see the point of John Harris's reply. Birding-aus received a zero-information e-mail from Marilyn and he replied with another. Net result two zero-information e-mails.
John, employ a filter to remove anything from Marilyn to birding-aus, then you'll never see anything from her again. I enjoy reading a slimmed down birding-aus with various filters (e-mail addresses and subject line keywords). This spring I didn't have to read anything about Twitchathons, for example, which was a great relief.
John Leonard
On 12/2/05, Bill Stent <> wrote:
So what you're saying is that the list should be receiving an apology
from Marilyn Davis any moment now...
Bill
-----Original Message-----
From:
[mailto:m("lists.vicnet.net.au","owner-birding-aus");">
] On Behalf Of Peter
Woodall
Sent: Friday, 2 December 2005 10:07 AM
To: Bob Forsyth
Cc:
Subject: Re: [BIRDING-AUS] Re: 400 Dead Pink-ears at WTP, Werribee
Hi everyone
I think that Bob is on the right track. If botulism is involved, it is
caused by
a bacterium Clostridium botulinum which is anaerobic, i.e. it can't
survive and
multiply in air/oxygen. Therefore in nature it is often found at the
edges
of water bodies
with much rotting vegetation which depletes the oxygen in the water and
mud.
C. botulinum is very widespread but only causes a problem when the
environmental
conditions are right for it to multiply.
The bacterium produces a neurotoxin that seems to affect the muscles of
neck
and wings first, preventing flight and causing the head to drop, and
later
death.
These signs are fairly diagnostic.
If other species were not affected they may have been feeding in
different
areas or
different depths of water.
Some species (like raptors) seem to have greater resistance to the toxin
and can
feed on carcasses without becoming affected themselves., but I think
that most
waterfowl are quite susceptible.
It is very widespread in North America, causing thousands of deaths each
year.
There are far fewer documented reports of it from Australia (I published
on an
outbreak of it in the Brisbane Valley in the 1970's) but I suspect that
it is
widespread but often overlooked.
Pete
At 07:21 PM 1/12/2005 +1000, you wrote:
>G'day all,
>
>It could be that is that the Pink-eared Ducks have a different feeding
>regime to other waterfowl ?
>They feed by filtering their food from the surface of the water whereas
>other species dabble from below the surface ?
>
>So, if a poison of some sort is floating on the water they would be a
goner !
>
>I am always amused that our Pink-eared frequently circle around closely
>behind each other in twos or threes with their beaks almost up the
>preceding duck's bum.
>
>Regards from
>Bob Forsyth
>Mount Isa, NW Qld.
>
>
>
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--
John Leonard
Canberra
Australia
www.jleonard.net
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