Landcare Research - Manaaki Whenua

Landcare-Research -Manaaki Whenua

Fowl smells could help native birds

Thursday 10 Sep 2015



A Kiwi scientist is following his nose and testing a novel approach which could help save nesting native birds from predators.

It is estimated 25 million native birds are killed in New Zealand every year by predators such as stoats, cats, rats and possums. Most of these introduced predators rely on smell to hunt. Landcare Research scientist Dr Grant Norbury hopes to use this instinct against them.

He plans to use generic bird scents, such as chicken or quail, in native bird habitat before they arrive to breed to encourage predators to investigate the smell yet receive no reward for their efforts.

“After several weeks, predators will lose interest in investigating the odour and we will have deceived them into thinking that bird odours are no longer a profitable cue for food,” Dr Norbury said.

“Naturally, once birds arrive to breed, predators will re-learn that bird odour can sometimes result in a reward. So, the idea is to give birds a window-of-opportunity to breed successfully before re-learning begins.”

The approach - referred to as “chemical camouflage” - has undergone preliminary tests by Australian scientist’s Dr Catherine Price and Dr Peter Banks, who will be collaborating with Dr Norbury on the research project. The Australian trial found a 60 per cent increase in the survival rate of nests over a short period.

Dr Norbury said native birds were at their most vulnerable when they were nesting.

“They’re essentially sitting ducks,” he said.

“Many of our birds have evolved behaviours that defend them from native avian predators, which hunt mostly by vision, but not from introduced mammals, which hunt mostly by smell. This has created a behavioural mismatch between the predators and vulnerable native species, and the results have been devastating.”

Dr Norbury said pen trials would begin early next month to establish how long it took predators to lose interest in the bird scent and how long that lasted. In the Australian study, rats lost interest in only three days.

“It’s important to realise that native species are mostly secondary prey for ferrets, cats and stoats. Their primary prey are often other introduced species like rabbits, rats or mice. This makes it easier to deflect predators’ attention away from native species for short periods,” he said.

He expected field trials to take place early next year in the Mackenzie Country. These would focus on whether the survival of braided river birds could be increased.

The two-year project was among 48 new research proposals recently granted $96.8 million by the Ministry of Business, Innovation and Employment. It was granted close to $1 million.