Rats and possums may be good for environment

Millions of dollars have been spent trying to control wilding conifers - which out-compete native plants and animals, and suck water from our catchments, there are fears they could cover 20 percent of land by 2030. But a new study has found the answer to controlling them might lie with animals we've traditionally known as pests, Scion invasion ecologist Tom Carlin speaks to Susana Lei'ataua.