Michael, birding Aussers,
Brodifacoum was the active ingredient used in the cereal based pellets
(at 20ppm I think) that were dropped on Campbell Island.
Yes, this poison would also kill non-target mammals/birds. Brodifacoum
is, as Michael mentioned very toxic to all mammals and birds, and is
usually used in preference to 1080 in eradications (rather than control
operations) in New Zealand due to the fact that it takes longer for
symptoms to occur, by which time animals have consumed more than a
lethal dose. This overcomes problems associated with rodents and bait
shyness. Furthermore, secondary poisoning is a very real problem with
this toxin, and during my Masters research on morepork here in NZ, I
found that 3 out of 14 radio-tagged birds died following a mouse
eradication attempt on a small island. Similar studies in other parts
of the world have shown the same sorts of effects.
However, there are no other mammals on Campbell Island that would be
affected, and the number of bird species likely to be affected by
poisoning is limited. Certain non-target species may be deemed to be
'at risk' to poisoning at the population level, and I suspect this was
the case with Campbell Island teal and snipe, some of which were removed
prior to the poisoning and re-released following it. Brown skua and
black-backed gulls are potentially the other main species to be
affected, and I would suspect a number of birds would have been killed
(guessing). There are no other pelagic raptors in the area. It would
be interesting to hear from recent visitors to the island as to numbers
of skua and gulls still present?
The situation in New Zealand is obviously very different to that in
Australia and most other parts of the world, where native/endemic
mammals may also be present.
I don't want to start an ethical 'argument', but at the end of the day,
if an eradication is successful (the success rate these days is pretty
darn good) then the removal of rats has to far outweigh the negative
short-term impacts involved in the poisoning of non-target animals.
This has to be one of the best conservation management tools in the war
against introduced rodents, and the people who have developed and are
using the technique to such great affect should be congratulated.
Cheers
Brent
Brent Stephenson
Eco-Vista: Photography & Research + Wrybill Birding Tours, NZ
email
http://www.eco-vista.com and http://www.wrybill-tours.com
|-----Original Message-----
|From: [owner-birding-
On Behalf Of michael hunter
|Sent: Thursday, 29 May 2003 7:22 p.m.
|To:
|Cc:
|Subject: Re: [BIRDING-AUS] Pest eradication - Victorian islands (Aust.)
|
|This begs the question.
|
| Would the poison pellets used on
Campbell
|Is. also poison native mammals &/or birds? Although the BBC news
report
|cited by Laurie doesn't mention the name of the poison used, an article
at
|the same news site refers to a spill of rat poison pellets into New
Zealand
|coastal waters on May 24th with potential environmental problems. That
|poison was brodifacoum, available here as Talon. This is an
anticoagulant,
|even WA mammals would be susceptible to it. (It being completely
different
|to 1080.)
|
| Brodifacoum is "very highly toxic to
|mammals
|and birds.It is extremely dangerous to birds through secondary
exposure,
|especially raptors feeding on poisoned rats and mice" (American Bird
|Conservancy). Also very toxic to marine life.
|
| How did skuas and other pelagic raptors
fare
|on Campbell Is? Maybe brodifacoum wasn't the poison used there.
|
| Which of Australia major seabird islands
have
|native mammals?
Birding-Aus is on the Web at
www.shc.melb.catholic.edu.au/home/birding/index.html
To unsubscribe from this mailing list, send the message
"unsubscribe birding-aus" (no quotes, no Subject line)
to
|
