Some parts of the Mackenzie Country are no longer
considered rabbit-prone, but farmers in other areas are not
so lucky. Photo by Stephen Jaquiery.
Environment Canterbury (Ecan) has started conducting
blood tests on wild rabbits to relay information to farmers
that North Otago populations of the pests are becoming more
resistant to the deadly calicivirus.
The virus was imported to New Zealand in 1997 to reduce
rabbit numbers, but Federated Farmers High-country Section
chairman Simon Williamson said most farmers still employed
people to shoot rabbits two or three times a year.
''Certainly the virus seems to be working to some extent, but
it's certainly not working like it was.
''You have to keep on top of them. They are becoming immune
to it in parts of the Mackenzie and Otago, where they are
having problems again.''
Mr Williamson said 200 rabbits were recently shot on his own
farm, which was between Twizel and Omarama, in just three
Environment Canterbury (Ecan) pest and biodiversity regional
manager Graham Sullivan said the council was already
undertaking a serological survey of rabbit blood.
''What we're doing there is monitoring the antibody levels in
rabbit populations to the calicivirus . . . at several
Mr Sullivan said although the Mackenzie basin remained
''highly rabbit-prone'', large rabbit populations were now
confined to ''large pockets'' of land in the Mackenzie basin
and North Canterbury.
''It's not the regional problem that it once was; land use
intensification has had a big role in that - large parts of
the plains are no longer rabbit-prone.''
Although two wet springs in a row had resulted in lower
rabbit numbers this year,
about 75% of rabbits in the Mackenzie Country were now immune
to calicivirus, and the serological survey was a way of
informing farmers of the situation. Waiting for the virus to
control the situation without the aid of additional culling
methods ''was not an option'', he said.
Mr Sullivan said Ecan's role was one of regulation and
monitoring, and the regional pest management strategy placed
obligations on land occupiers to take measures to control
Ecan found ''high levels'' of compliance among landowners.