The Department of Conservation (DOC) says the “toxic component” of its aerial operation in the Makarora area will take place today (Saturday April 27).

The 1080 drop is part of a rat and stoat control operation in response to high rat numbers resulting from a beech mast season in 2023.

“These rodents seriously threaten the survival of the mohua populations in the area, and negatively impact other native species,” DOC said in a statement. 

During the operation, helicopters will be sowing toxic cereal pellets across a roughly 36,000ha area including the Makarora, Blue, Young, Siberia and Wilkin Valleys.

The pellets are about 3cm long, cylinder-shaped and green, and DOC warned that they should not be touched; they are deadly to dogs, and anyone in the area with children should watch them at all times.

There will be a handful of closures in place until at least Sunday (April 28) due to the drop including the Blue Pools carpark and the area immediately around it, the Cameron Flat Campground and the Siberia Airstrip and Jumboland Airstrip. 

“If weather or other issues cause the operation to extend into Sunday these closures will be extended until 11am on Monday,” DOC said.

DOC signalled the rat and stoat control operation in February.

An increase in food supply from the recent heavy seeding event (also known as a mast season) caused the surge in introduced predators including rodents and stoats.

During one of these events, a larger number of tree seeds are produced, which should benefit native species.

Instead, this can be hijacked by introduced predators and, a few months later, with all the seeds eaten, the rodent population turns to eating native species.

DOC said it had been monitoring rodent numbers in the area and found they had reached “critical levels”. 

“There are rare native species here that will suffer heavy losses if we don’t act, including mohua, whio, kākā, kākāriki, rock wren/pīwauwau and bats/pekapeka,” DOC said.

DOC said today’s 1080 drop is weather dependent.

“If difficult operating conditions are encountered on Saturday work may continue into Sunday.”

PHOTO: Sarah Forder