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Smelly Solution

Otago University Wildlife Management students are testing a new chemical lure for ferrets.

"As ferrets move about their home range, they deposit a scent produced in their anal glands. Ferrets are naturally curious and are attracted to each other's scent marks. We are try ing to trick ferrets into artificial scent lured traps so we can better trap and kill them," says Dr Henrik Moller, director of the Diploma in Wildlife Management.

Ferrets, introduced in 1879 to control rabbits, have become pests themselves. They prey on many flightless and ground-dwelling native birds. On the Otago Peninsula, they are thought to be responsible for the death of many yellow-eyed penguin chicks from the Boulder Beach breeding colony.

Traditionally, ferrets have been controlled with the use of meat-lured traps. The main drawback is that once dried out, the meat fails to attract ferrets. Many non-target species, such as domestic cats and dogs, are also attracted to the traps. In contrast, chemical lures should attract only the target species.

DSIR Chemistry scientists, working in collaboration with chemical lure specialist Dr Kay Clapperton, have identified 2-n-propylthietane as the major component of the scent. Several concentrations of the chemical have been prepared in a paraffin suspension, which acts as a slow release mechanism so the lure remains attractive longer. The end result is described as smelling like "a whole heap of musty ferrets".

The students are trying to work out the right concentration of lure for traps. Since mid-July, traps have been laid around Boulder Beach, and data is being collected on the effectiveness of various concentrations.

"It could take a long time to develop the right lure at the right concentration, but it will be well worth the effort if an effective conservation management tool results," says Moller.

Lynda Gray, Otago University