http://www.abc.net.au/science/news/enviro/EnviroRepublish_1429383.htm

Feral cats lured by sausage bait
Anna Salleh
ABC Science Online

Thursday, 4 August 2005

The new bait has been designed to interfere with the ability of feral
cats to carry oxygen in their blood (Image: Michael Johnston)

New toxic bait that looks like cocktail sausages could stop feral cats
from killing Australian native wildlife.

The bait is made of kangaroo meat and chicken fat laced with a chemical
that's poisonous to cats yet is less likely to harm native animals.

It puts feral cats to sleep, killing them within an hour by a process
similar to carbon monoxide poisoning.

"It's very rapid and seems to be a very peaceful process," says team
member Michael Johnston, a research scientist with Victoria's
Department of Primary Industries.

Cats were brought to Australia by settlers and by the 1850s there were
feral cat colonies in the wild. Cats were also deliberately released in
the late 1800s to control rabbits, rats and mice.

There are now millions of feral cats around Australia, pests that have
caused native animals to become extinct on some islands, and have
threatened ground-dwelling birds and mammals on the mainland.

Current ways of protecting native animals from cats in Australia's
national parks like shooting, trapping and fencing are too expensive to
be used over large areas, says Johnston. So he says baits are
necessary.

One of the challenges in baiting pests is making sure that native
animals are not affected.

Johnston says he has dredged the literature to find a toxicant, called
para-aminopropiophenone (PAPP), which was once used by the military but
could now become a cat-specific bait poison.

Shooting feral cats is not practical over large areas, say researchers
(Image: John Robinson)
PAPP can be used to treat human radiation sickness and cyanide
poisoning. But in cats it induces a lethal case of methaemoglobinaemia,
in which the blood's haemoglobin is oxidised to a form that cannot
carry oxygen.

Johnston says tests on feral cats in the laboratory show that within 20
minutes the animals become lethargic, are unconscious within 40 minutes
and dead within an hour.

"It's something that we think is a very humane method," he says.

Johnston says evidence from the literature shows cats are more highly
susceptible to developing methaemoglobinaemia than other animals,
making PAPP a good candidate for bait.

"Brushtail possums are 90 times less susceptible than cats to PAPP,"
says Johnston. "So there is a significant margin there."

Colleagues from the Pest Animal Control CRC in Canberra are testing the
possible use of PAPP baits on wild dogs and foxes, and will also be
further testing the chemical's impact on Australian native wildlife.

The researchers also hope that formulating the poison as large hard
pellets will reduce the chance native animals will eat it.

The bait is formulated to look like cocktail sausages (Image: DPI)
Johnston says this is because while feral cats tend to swallow their
food in relatively large portions, native animals tend to chew their
food very carefully and are likely to spit out the poison pellet when
they find they can't chew it.

Another challenge the researchers face is finding a bait that will
interest cats, which don't generally eat dead flesh.

Western Australia's Department of Conservation and Land Management has
identified kangaroo and chicken fat as key ingredients for an
attractive bait, says Johnston.

It has also found the baits are best laid in the winter when there is
less alternative food around for the cats and they are using a lot of
energy.

Johnston hopes to see field trials of the bait before the end of the
year.