Poisoning campaigns may be vital this winter if rabbit haemorrhagic disease (RHD) is to continue to keep rabbit numbers down, says Landcare Research scientist John Parkes.
"There are patches in Central Otago that are getting back up to where they were [before RHD] and with higher levels of immunity among the
survivors."
Poisoning programmes using 1080 this winter could decimate the immune populations, allowing RHD to again keep a lid on populations in those areas, he said.
Shooters killed 20 per cent more rabbits at the weekend's Great Easter Bunny Hunt, raising the spectre of a growing rabbit population immune to the disease.
A total of 9128 rabbits were killed in this year's hunt, up 1635 on last year, but well below the 1997 record of 24,000 in 24 hours.
Increasing purchases of ammunition by farmers also point to a burgeoning rabbit population after a bumper breeding season.
Sales of guns and ammunition fell by up to 70 per cent after the release of RHD in 1997, Dunedin sports store owner Scott Kunac said.
"Probably for the past three years it's been increasing again every year. It's still not to the level it was originally, but it's certainly bigger than it was."
Otago Regional Council regional services manager Jeff Donaldson said the council was planning a poisoning campaign again this winter, after a successful programme last year.
"When rabbit numbers creep up to a certain point, the only option is to poison them. On some properties immunity is building up and the virus is not working as well."
Mr Donaldson said rabbit numbers overall were still not close to those before the virus was introduced.
Mr Parkes, who heads Landcare's RHD research effort, said the virus was still working well in some areas such as the Mackenzie Country, but elsewhere immunity had built up to the point where extensive poisoning was needed.
Farmer Donald Young, whose Lowburn property was the first found carrying RHD in 1997, said he was poisoning again for the first time. He was also buying more ammunition.
He said a long breeding season had probably helped to increase rabbit numbers.
- NZPA
Herald Feature: Conservation and Environment
Related links
