​Environmentalists fear hundreds of birds may have been killed in a 1080 drop in Otago but Department of Conservation (DOC) staff say no such conclusion can be made.

On Monday DOC announced six of 12 monitored kea in the Matukituki Valley, near Wānaka, died following an aerial 1080 predator control operation.

1080 drops, revised to deal with an explosion of rodents during last year's "mega mast", have yielded contrasting results in Kahurangi National Park.
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The Department of Conservation (DOC) said the revision had proved a success overall, nationwide.

Native bird populations could be completely wiped out in some areas hit by this year's mega mast.
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It's set to be the biggest seeding event in more than 40 years, but half-a-million hectares of forest will receive no 1080 predator control.

​The Department of Conservation says a recent 1080 drop in Fiordland was to curtail an exploding rat and stoat population.
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The Department dropped 1080 in the Arthur Cleddau area and Bowen catchment area on Tuesday.

The rat population in a piece of pristine bush has exploded thanks to a plethora of beech tree seeds, forcing the Department of Conservation to make a 1080 drop.

But the glut of food means it can be difficult to get rats to eat the poison.

Three hundred tahr are to be culled and fed to kea in an attempt to keep the endangered native parrots away from an aerial 1080 poison drop in the hills behind Whataroa.
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Zero Invasive Predators (Zip) was last month granted permission from the Department of Conservation for intensive predator control in an attempt to eradicate possums and, potentially, rats, from about 12,000 ha of rugged backcountry at the Perth River.

In an unexpected result, scientists encountered more deer in South Westland forest blocks after 1080 drops than before the drops.
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They also encountered and saw the same numbers of deer in 1080 drop zones as they did in zones where 1080 was not dropped.

The question, just how much collateral damage does 1080 poison do, could soon be answered through a peer-reviewed study commissioned by the Marlborough branch of the New Zealand Deerstalkers Association.

The SPCA has changed its stance on the use of 1080, only a month after it called for a ban on the pest-control poison.
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Last month, the charity said it was" deeply concerned " over the use of 1080, and the use of poisons to kill animals due to the level of suffering they caused.

​The University of Auckland's Dr Cate Macinnis-Ng makes a case for why we can't leave our vulnerable native species to fend for themselves in forests where predators roam.