Greedy birds to feast on poison

MOB RULE: Rooks can wreak havoc in summer when they band together in large flocks and arrive in crop paddocks en masse. PHOTO/FILE

The Greater Wellington Regional Council is working to make Wairarapa rook-free and is locating nesting areas in the region.

Council biosecurity officer Steve Playle said his team would begin baiting within the month to control the population, which will minimise crop devastation.

"In low population, the damage is often light," Mr Playle said.

"But the thing is, after the breeding season you can get flocks of 200-300 birds, and when you get that sort of situation, it is really bad news for precision crops like maize, beans and peas.

"In a big mob, they'll land in the middle of a paddock and work their way out.

"They'll basically strip the seed out of the ground and you're left with big bare patches.

"So that's one of the reasons we've been so active in trying to control the numbers over the years, because we have seen occasions in which the damage has been quite severe."

The council's rook eradication programme began in the late 1980s and has since reduced numbers of the pest.

"I've got about 116 sites on our database at the moment, which we actually go around to and have a look at with the helicopters," Mr Playle said.

"Last year out of all of those sites we had eight active rookeries so it's not a big number."

Once the surveying in the region is completed, the council's biosecurity team will wait for a fine day to complete baiting.

The baiting is done by an operator suspended on a chain underneath the helicopter.

The bait and toxin are applied with a corking gun into the nest manually.

"So it's not like a blanket operation," Mr Playle said. "It's very precise and we know where all the bait goes. Our operators know the difference between a rookery and, say, a blue-heron nest, so we're only treating the right nests, not at random.

"It's a precision operation."

Mr Playle said that generally most rookeries were found in Northern Wairarapa, but the council had found active ones along Te Ore Ore and Upper Plain roads.

Landowners, contractors, and anyone who knows the location of an active rookery are asked to contact the council with details.

"We are keen to hear from those who might have called us in the past, as well as those finding rooks for the first time," Mr Playle said.

"It's important that property owners don't try to poison or shoot any rooks they find. These are wary birds and will quickly disperse and establish more rookeries."

Council biosecurity officers would control the rooks at no cost to the landowner.