How we can out-sniff a kiwi-killing predator

Kiwi researchers have just found a clever new way to use stoats' sniffing-power against them. Photo / Patrick Garvey

Researchers have happened upon a clever new way to fool a notorious kiwi-killing predator - by using its own sense of smell against it.

Experiments by Auckland University and Landcare Research have revealed that stoats, the major killer of young kiwi chicks in the wild, are attracted to the smell of their two biggest enemies, cats and ferrets, raising the possibility of using their scent as a lure for traps.

It was a finding that surprised university doctoral student Patrick Garvey, who was expecting the stoats to be scared away by the smell of the larger predators, instead of being drawn to them.

Kiwi researchers have just found a clever new way to use stoats' sniffing-power against them. Photo / Patrick Garvey

This was because an earlier study he led had found captive wild stoats to be scared when cats or ferrets were near.

In the new study, food was placed in two locations where the scent of cats or ferrets was absent, and also in another area where scent was present.

Garvey found that in the area that smelled of predators, the food was actually eaten faster.

Despite the baffling finding, he felt the research represented an untapped area of predator control, effectively using mammals' tendencies to hunt by smell against them.

The ability of stoats and many other mammals to "eavesdrop" on the olfactory communication system of larger predators could be the beginning of the search to develop odour-based lures in pest trapping operations, he said.

"By hijacking the olfactory communication systems of predators such as stoats, we may be able to exploit an invasive predator's most instinctive behaviour, which is to inform themselves about their environment through the sense of smell."

Little was still known about these processes, and exploiting them could help towards the Government's just-announced bold bid to rid the entire country of pest predators by 2050.

"It's something new, and it's something that can be used as part of other methods to ensure we do the best we can for conservation."

The study comes amid a new two-year, million-dollar trial by Landcare Research to shield vulnerable and breeding birds from predators by using what's been dubbed "chemical camouflage".

The approach involved using generic bird scents, such as chicken or quail, to lure predators to native bird habitats before they arrived to breed, leaving them with no reward for their efforts.

Once the predators were deceived into thinking there was no prey in that area, the birds could arrive to breed and had a window of opportunity before the pests came back again.