Scientists using ‘fake news’ to stop predators killing endangered birds
Scientists used ‘fake news’ to stop predators killing endangered shorebirds — and the result was remarkable.
This article has been republished from The Conversation under Creative Commons licence CC BY-ND 4.0.
South Island pied oystercatcher tōrea
The South Island pied oystercatcher tōrea, Haematopus finschi, is endemic to Aotearoa. They usually breed inland on the South Island before most of the population moves to coastal areas in the North and South Islands. Their ‘nests’ are just scrapes on a mound or a raised area of sand, gravel or soil.
Animals, including humans, depend on accurate information to navigate the world. But we can easily succumb to deliberate misinformation or “fake news”, fooling us into making a poor choice.
The concept of fake news came to the fore during the term of former US president Donald Trump. It became so prevalent, it was named the Macquarie Dictionary’s word of the decade.
In a new paper we show how a form of fake news can be deployed to help save vulnerable wildlife. We protected endangered shorebirds by spreading misinformation — in the form of bird smells — to deceive predators. This helped reduce the number of birds lost, without using lethal force.
To be honest, when we began working on the idea ten years ago it seemed a little crazy. But after seeing how fake news messes with the minds of both humans and animals, it now makes a lot of sense.
Double banded dotterel tūturiwhatu
The double banded dotterel population in New Zealand is classified as nationally vulnerable and is declining. They lay their eggs in shallow scrapes in gravel, sand or soil so are at risk of predation.
The problem with predators
Introduced or ‘alien’ predators are species such as rats, cats and foxes, which have been introduced to new environments and kill local wildlife. If local species have not evolved with such predators — and so learned to evade them or ward them off — the damage can be devastating.
Alien predators have far more impact than native ones and are a major driver of extinctions. In Australia alone, cats threaten the survival of more than 120 listed species, while foxes threaten 95 species. In the South Pacific the threat is even greater.
But killing predators is a blunt and often ineffective tool. Too often, control techniques such as baiting, trapping and shooting can’t reduce predator numbers enough to protect vulnerable prey.
In other circumstances, lethal control may not be possible or socially acceptable. This might occur when the problem predator is a native species (such as foxes in the United Kingdom ) or where alien predators such as feral pigs are also a food resource for local people.
That’s why it’s important to examine alternative ways to protect vulnerable species.
Feral cat
A feral cat investigating a camera trap at the MacKenzie Basin. Cats are a threat to our native species as they eat eggs and also kill endangered shorebirds.
New Zealand’s precious shorebirds
In New Zealand, 59 bird species have become extinct since humans arrived and many more close to being lost. Introduced predators contribute substantially to this problem.
Predators such as hedgehogs, cats and ferrets were introduced to New Zealand in the 1800s. They are especially common in our study area, the braided riverbed landscapes of the Mackenzie Basin on New Zealand’s South Island. There, they eat eggs and kill endangered shorebirds such as banded dotterel, plovers, wrybill and the South Island pied oystercatcher.
The birds evolved with avian predators, and have learnt to hide from them by building camouflaged nests among pebbles on the river shores.
But this tactic does not work against introduced predators. Odours emanating from the shorebirds’ feathers and eggs attract these scent-hunting mammals, which easily find the nests.
Tricked you!
Our research set out to undermine the predators’ tactics. We worked closely with Grant Norbury and others from Manaaki Whenua Landcare Research in New Zealand.
We distributed fake news – in the form of nest-like odours – that suggested to predators the shorebirds had begun to nest, even though they were yet to arrive.
First, we distilled odours extracted from the feathers and preen glands of three bird species – chickens, quails and gulls. In this case, any bird species could be used to produce the scent. (Watch a YouTube video of the process here). The result smelled a lot like a chicken coup or aviary – unmistakable to the human nose.
Five weeks before the shorebirds arrived for their breeding season in 2016, we mixed the odours with Vaseline and smeared the concoction on hundreds of rocks over two 1,000-hectare study sites. We did this every three days, for three months.
The predators were initially attracted to the odours. But within days, after realising the scent would not lead to food, they lost interest and stopped visiting the site.
Predators investigating the ‘fake news’ smells
These images show a cat, hedgehog and a ferret investigating the odour paste treatments at Mackenzie Basin.
The shorebirds then arrived at Mackenzie Basin at their normal breeding time, and began building nests and laying eggs. At control sites where our 'fake news' had not been deployed, the predators ate eggs and birds at the usual rate. But at sites where we put out unrewarding bird odours, the results were dramatic.
The number of nests destroyed by predators almost halved. As a result, chick production was 1.7 times higher at treated sites compared to control sites over the 25-35 days of the nesting season.
We wanted to be sure our results were not due to lower predator numbers or different behaviour in some areas. So the next year, we flipped treatments at our sites and got the same result.
Grant preparing a camera trap at Tekapo
Dr Grant Norbury of Manaaki Whenua – Landcare Research worked with colleagues at the University of Sydney on the project. Here he sets a trap to see if using unrewarded prey odour cues could fool predators, and make them ignore real prey cues.
Using fake news for good, not evil
Our modelling predicts this fake news tactic would increase plover populations by about 75% over 25 years. By comparison, an absence of intervention would lead to a population decline of more than 40%.
Our results show the profound conservation potential of fake news tactics. The approach cost no more than a traditional lethal control program and delivered comparable benefits.
We hope the work will encourage others to consider manipulating the behaviour of introduced predators when lethal control options are too difficult or ineffective.
Related content
Find out more about New Zealand's mission to be pest predator free by 2050.
Find out about other forms of pest control, including recent technologies, in Alternatives to 1080. This slideshow presents some of the pros and cons of other methods of predator control that can be used to protect our native birds.
See these recorded PLD webinars:
Pest detectives will help scaffold student investigations into plant and animal pests.
Tame Malcolm – indigenous pest management hear examples of how both mātauranga and science have been part of Tame’s journey.
The Connected article Bringing back the birdsong looks at how students worked with the Department of Conservation and Fiordland Conservation Trust to increase the population of native birds in Fiordland.
The article Cat fight looks at the effects cats have on our native species and what could be done to reduce their adverse impacts.
The Science Learning Hub team has curated an introductory collection of resources to help teach about bird conservation. You can copy and add the collection to your own profile, where you can edit and curate additional resources. The article Creating collections tells you how to get the most out of a collection.
Activity ideas
ZEALANDIA, with support from WWF New Zealand, has produced a comprehensive teaching resource supporting New Zealand schools to explore the pest-free vision with students.
In the activity Making a tracking tunnel, students monitor the presence of pest species in a neighbouring gully or their school grounds
Useful links
See the full paper, Misinformation tactics protect rare birds from problem predators.
This YouTube video Chemical camouflage using fowl smells features scientists from Manaaki Whenua – Landcare Research who were part of this research project.
Use the Pest Detective online guide to help identify signs left by pest animals.
Predator Free NZ is a very useful website, with lots of information.
Acknowledgements
This article was written by Peter Banks, Professor of , School of Life and Environmental Sciences, University of Sydney and Catherine Price, Postdoctoral Researcher in , University of Sydney.
The article was originally published in The Conversation, 1 March 2022. Read the original article.
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