With the mast seeding event over, the pests were beginning to starve, he said. Landcare Research ecology research Dr Adrian Monks said rat and mice numbers were still increasing, but they had almost peaked. "The primary cue for triggering a mast event is a warm summer in the previous year. This year [2019] was an extremely large mast event [extremely high densities of seeds] triggered by an extremely warm January and February in 2018. "Another scenario is that trees could produce large crops every second year."

Source: Otago Daily Times December 26, 2019 15:00 UTC