Tuesday Chewsday, a citizen science project, led by Heidy Kikillus, a post-doctoral fellow at Victoria University, will categorise the types of non-native species, such as mice, rats, possums, hedgehogs and stoats, living near Karori’s Zealandia sanctuary.

“Suburban invasive pests are one challenge native birds face when they disperse from Zealandia,” says Heidy.

Over 200 randomly selected homes will place ‘chew cards’—small rectangle cards infused with a peanut butter blend—on their properties for the next week before leaving them in their letterbox for collection.

“Mammals such as rodents and possums are attracted to the cards and nibble on them, and afterwards we can tell who has visited based on the bite mark pattern,” says Heidy.

“We hope to gather baseline data about the city’s resident pest population. This will allow us to monitor any changes when we repeat the survey in a year or two.”

Chewcards are often used in forested areas, but this is the first time they have been distributed on a large-scale in a city environment.

Another part of the study will determine the effectiveness of chewcards in suburban gardens. In other words, says Heidy, are chewcards tempting enough to nibble on when there are also things such as compost bins and pet food around?

“I am delighted at the level of interest shown by Wellingtonians in this project. It’s a simple way for local residents to get involved in conservation and learn a bit more about their surroundings.”

For more information email heidy.kikillus@vuw.ac.nz