Chocolate found to be effective for pest control

Greater Wellington Regional Council and Wellington City Council are taking the phrase "Death by chocolate" to a whole new level with an innovative rat control method - using chocolate instead of poisonous bait.

The councils are partnering to investigate how well rat numbers can be controlled without poison at Te Ahumairangi (formerly Tinakori) Hill.

"As far as we know this area doesn't have possums so is an ideal trial site to focus on the rodent population," says Senior Biosecurity Officer Paul Horton.

Greater Wellington's biosecurity team has set up several self-setting traps made by Kiwi innovators Goodnature. The traps feature chocolate lures that attract rodents with their sweet smell and then instantly kill any curious rodents.

The lures are designed to last six months and the trap can kill 24 rodents before CO₂ needs to be replaced.

"This is just one method we can use to get our rodent populations under control," says Paul. "Because the traps can be used more than once before checking it would save staff time spent checking traps regularly. Plus, native birds aren't drawn to the traps and cannot interact with the bait."

According to Daniela Biaggio, Urban Ecology Manager for Wellington City Council "to protect biodiversity in urban environment we need to continuously  improve what we do and how we do it. This is a great example of how we embrace new ideas and innovation so we can stay ahead of our biosecurity challenges and have a city thriving with wildlife."

The rodent numbers on Te Ahumairangi Hill are being monitored by tracking tunnels & cards in tunnels with ink on the floor that show footprints. These are showing numbers remaining at low levels. The site also has chew cards with peanut butter smeared on them. Staff are able to see what kind of pests are visiting by looking at bite marks left in the cards.