Timing halts pests in lockdown
A little luck with timing has helped out most of New Zealand’s threatened native species during the Covid-19 lockdown.
Though back country pest control work remains on hold, an army of backyard trappers has continued catching rats, mice and other pests without leaving their properties.
The season has helped conservationists and threatened wildlife, and most pest species are not breeding in the lead up to winter, meaning their numbers have not exploded.
When the lockdown began in March, the Department of Conservation’s (DOC) predator control programme, Tiakina Nga¯ Manu, had almost finished its largest ever season, a response to the 2019 mega mast (heavy seeding) in the South Island.
Predator control had been carried out on about 850,000 hectares of conservation land, out of a planned 900,000ha. Of this, 780,000ha was controlled with 1080 poison.
Programme manager Peter Morton said that would have protected the species most at risk, such as orange-fronted parakeet (ka¯ ka¯ riki karaka), kiwi, ka¯ ka¯ , whio (blue duck), and bats.
Morton said stoats and weasels bred only once a year, in early summer, while possums reproduced once or twice a year. Rat breeding would have slowed or stopped as food became more scarce.
However, rats, stoats and possums would spread into new areas and could re-invade places where they had previously been controlled.
Delaying predator control in some places would increase the chances of some native animals being eaten, especially stoats predating kiwi chicks, but it was ‘‘not expected to have a critical impact’’ on species’ populations, he said.
‘‘Fortunately, most native birds have finished nesting, which is when they, and their eggs and chicks, are most vulnerable to predation,’’
Among the growing number of backyard trappers bolstering council and community group pest control efforts and keeping traps baited is Lynette Hartley.
Hartley has Department of Conservation 200-type box traps on her native plant-clad property in Westmorland, Christchurch, which backs onto a reserve.
She said she had trapped weasels, hedgehogs and rats, and was catching mice in her garage ‘‘like it was going out of fashion’’.
Lockdown had not really changed her trapping habits, and she knew of others who had also kept it up.
Hartley is part of Predator Free Port Hills, a project led by Christchurch’s Summit Road Society. It is one of about 70 backyard trapping groups across the country.
Secretary Marie Gray said the group had 1000 backyard
Peter Morton
Department of Conservation’s predator control programme manager
Morton said.
A planned 1080 drop at Wet Jacket Arm in Fiordland has been delayed. It would have been the first in an area that has experienced ‘‘devastating’’ impacts from stoats killing kiwi trappers and aimed to increase that to 4000. Its whole network was able to be checked during the lockdown because it was just in people’s backyards.
The group had been holding trapping workshops on Zoom and making more of an effort on social media.
Gray said people had reported catching more rats recently, but this happened in autumn every year as temperatures changed.
over several years, he said.
Other drops on the West Coast, and in the Aorere region of Kahurangi National Park — which is home to at-risk carnivorous snails, kea, whio, great spotted kiwi and takahe¯ — were also delayed. They will not take place until the Covid-19 restrictions ease.
A 6000ha stoat trapping network in another part of the Kahurangi is one of many ground-based back country trapping networks for which monitoring is on hold while alert level three is in place.
‘‘Fortunately, most native birds have finished nesting, which is when they . . . are most vulnerable to predation.’’