Enzo M.R. Reyes
Invasive mammalian predators threaten wildlife and even cause extinctions of their prey in many places around the globe. The impact of invasive mammalian predators on islands is especially strong, because many island species evolve in an environment free of predatory mammals, and lack antipredator behaviors. They become easy prey.
New Zealand is a good example of this; it is one of the countries with most bird extinctions due to introduced mammalian predators such as rats and weasels. As such, the country is invested in predator control using innovative techniques.
A new study conducted in New Zealand and published in Science Advances details how a group of researchers made use of the mammalian predators' keen senses of smell to fool them, by using "misinformation" in the form of fake prey scents. The experiment was designed to make predators (ferrets, cats and hedgehogs) less efficient at hunting using a paste made from the carcasses and feathers of quails, gulls, and chickens — three common bird species. The idea was to habituate the predators to smelling these birds without encountering them, thus tricking the predators into ignoring other bird smells as well.
The researchers exposed the predators to the smell of the paste for five weeks before native birds began to nest, then monitored their attacks on native bird nests for eight weeks after that. The experiment reduced the frequency of nest attacks and increased the number of eggs hatching 1.7-fold, at minimum doubling the odds of successful hatching during the experiment. Furthermore, using these numbers, the researchers modelled the potential population increases for native birds if the treatment was used for 25 years, and found that it could increase bird populations by 127 percent.
The experiment showed that using misinformation can affect predator behavior, making them lose interest in endangered species. Furthermore, the technique is cheaper than conventional lethal predator control methods such as trapping and poisoning.