Rabbits thriving in dry Central region

A lack of spring rain has created rabbit-friendly conditions that could create more problems for Central Otago farmers this summer.

It has been a bumper spring for young rabbits, with low rainfall meaning fewer were drowned in burrows.

Otago Regional Council regional manager Jeff Donaldson said the low rainfall had created ideal feed conditions – rabbits prefer short grass – and perfect breeding conditions.

"At the moment we're telling landowners they've got an issue."

If it continued to dry off, the council may help some landowners with oat poisoning in late summer, while others would have to consider winter poisoning, he said.

But poisoning would depend on how much feed was available, because rabbits would not change to other types of feed if there was still enough grass, Mr Donaldson said.

RHD was still working but could not compete with the level of reproduction that was occurring. "The virus is only a tool, it's not a silver bullet. It won't take out the numbers of rabbits it did initially, ever again," he said.

Landowners would have to rely on fumigation, shooting and poisoning to keep numbers down.

Adapting habitat would also help – rabbits leave irrigated land because they do not like long, green grass, he said.

"They like it dry, they like it warm and they like it short."

Good rabbit habitat has less than 400mm of rain, light soil, good drainage, shelter near short grass, and is sunny. Unfortunately, most of Central Otago fitted that criteria.

At a biosecurity conference in October, Mr Donaldson said some Central Otago landowners were spending more than $100,000 on rabbit control.

A shortage of cheap carrots had also been hampering poisoning programmes because it drove up costs, he said.

Environment Southland biosecurity officer Tim Riding said rabbit numbers in Southland had been gradually declining during the past decade. There were pockets in some areas that were watched more closely.

Hare numbers were rising but a pair produced only three to four offspring a year, compared to a pair of rabbits, which could potentially produce up to 150 offspring.

It was unlikely hare numbers were likely to "explode", he said.

- © Fairfax NZ News

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