Folks,
listen well to Jenny. The 'bad news' item in The Age gives the opinion of
an uninformed journalist, typical of the shock, horror news peddlers that
infest the media. Feral animals on islands are the bad news, wherever they are
encountered. The documented history of their effects is a story of devastated
and extirpated avian populations. Seventeen Procellariform species, some 17%
of the total, breed on Macquarie, Some of these are critically endangered, and
may well be taxonomically distinct from 'conspecific' populations on other
islands.
All petrels are K-selected, having a longlife and late of maturation and the
security of their populations is dependent upon 3 parameters, adult annual
survival rate (typically 90-97%), breeding success (>60%) and survival of young
to breeding age (>40%). Reduce any of these and populations decline. Rabbits
cause catastrophic erosion, preventing adults from digging burrows, and causing
burrows to collapse and entomb the contents. Rodents eat adults, chicks and
eggs. The mortality caused is a potential threat to the survival of any petrel
population. On Gough Island in the Indian Ocean, the apparently inoffensive
little house mouse kills chicks (of all ages) of the large Tristan Albatross
(Diomedea dabbenena). These little stinkers chew their way into the interior of
the chicks and eat them alive from the inside.
Well documented are the recoveries of petrel populations following the
removal of feral mammals from breeding sites. The recovery of Gould's Petrel
on Cabbage Tree Island NSW is a classic example. The Macquarie Island exercise
was essential and long overdue. It was well planned and the loss of some
individuals of non-target species was recognised and expected.
Black ducks on Macquarie Island may be refugees from Victorian shooters, but
whatever their provenance, the proximate abundance of this species is very
dependent on rainfall. After breeding they disperse to all points of the
compass, and those that find Macquarie Island may be just some of the lucky
individuals. If they get a dose of poison, then their luck just ran out. Some
more will turn up following the next breeding season.
For further reading just Google' rat extermination', and there is a wealth
of information to be found.
Cheers
Harry Battam
BE, PhD
Institute for Conservation and Environmental Management
University of Wollongong
Wollongong, NSW, Australia 2522
Mobile +61 429 887 883
________________________________________
From:
on behalf of jenny spry
Sent: 18 October 2011 17:27
To: Jeff Davies; birding-aus
Subject: Bad news from Macquarie
Hi all,
I agree with Jeff Davies on this. Yes, the bird deaths are sad but we I
believe we should be looking at the longer term results.
Another thing that is not mentioned in this article is the number of chicks
and birds eggs that the rats would have eaten each breeding season. I
imagine that could easily have been 2000 bird deaths per year for the last
hundred years or so.
As for the rabbits they have been destroying the habitat and thereby
limiting breeding habitat for prions etc as well as making the burrows more
vulnerable to attack from Skuas. For example an item on the Macquarie Island
website recently mentioned that Grey Petrel breeding numbers have increased
recently, possibly due to less predation from rats.
Let's wait and see what the island looks like once the mega herbs regrow and
breeding is allowed to occur without predation by rats land clearing by
rabbits. Maybe right now our support needs to go to the people doing the
eradication, rather than jumping in league with the politicians and
newspapers, both of whom love an apparent bad news story.
The ducks in question are Pacific Black and, again, it is sad to see them
die, but they are not an endangered species as many of the seabirds that
breed on the island are.
cheers
Jenny
On Tue, Oct 18, 2011 at 4:57 PM, Jeff Davies <> wrote:
> G'day Dave,
>
> I think you need to put all this into perspective, is a one off hit like
> this worse than doing nothing? Let's revisit this in ten years time or
> earlier and see what the improved situation is going to look like without
> the ferals eating and digging the place into oblivion.
> Since when has Eric Abetz ever been a voice worth listening to on the
> conservation front.
>
> Cheers Jeff.
>
>
>
>
> -----Original Message-----
> From:
> On Behalf Of Dave Torr
> Sent: Tuesday, 18 October 2011 4:35 PM
> To: Peter Shute
> Cc:
> Subject: Re: [Birding-Aus] Bad news from Macquarie
>
> Indeed - you can't expect 100% accuracy from a newspaper! But it is
> disturbing that something that was supposed to be protecting the birds
> seems
> to have the opposite effect - especially as the total kill seems likely to
> be somewhat higher.
>
> On 18 October 2011 16:31, Peter Shute <> wrote:
>
> > What sort of ducks? And what percentage of the total is 2000.
> >
> > There seems to be some confusion about how they were poisoned.
> >
> > Peter Shute
> >
> > --------------------------
> > Sent using BlackBerry
> >
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