Wasp battle begins
The wasps at Nelson Lakes have been given their marching orders.
Department of Conservation (DOC) rangers and community volunteers armed with Vespex, walking boots, and a helicopter, have been out and about since last week.
Nelson Lakes senior biodiversity DOC ranger Nik Joice said the community involvement had been fantastic, particularly from the community group Friends of Rotoiti.
‘‘Having them help out, and the funding from the [Stuff’s] Wasp Wipeout programme, means we can do much more than we could on our own. And having the helicopter means [the volunteers] get an experience they might not have otherwise.’’
Joice said getting poisons to bait-lines could be hard work, but the beauty of Vespex was the small amount needed to be effective. This year’s entire Vespex supply at St Arnaud weighs just 60 kilograms, and is expected to wipe out more than 90 per cent of the wasp population.
‘‘It’s the easiest bait programme ever, because the most you carry is three kilograms,’’ Joice said.
This is the first time rangers at St Arnaud have used a helicopter to bait wasps, which they are using to reach further afield than ever before, baiting along the 80km Travers-Sabine circuit tramp.
Trap lines are 300 metres apart, with about 50m between each bait station, up to 900m above sea-level. Over a few days, each station will be filled with about 20 grams of Vespex bait, left for a few days, and then cleared of any remaining bait.
‘‘That first afternoon once the bait is out is when you get the most wasps . . . it’s incredible how it works, it’s like flipping a switch,’’ Joice said.
Usually when they clear the bait stations, wasps have taken most of the bait, but Joice said it was ‘‘best practice’’ to remove the unused bait anyway.
‘‘The longer it’s in the environment, the more impact it has,’’ he said.
‘‘The wasps take up to 50 per cent of the bait on the first day; as a general rule, there’s not much left, maybe 25 per cent left after the first few days.’’
The traps are baited in the morning, when wasps are still ‘‘getting their carbohydrate fix’’, Joice said. In the afternoons, the wasps start collecting protein to take back to the nest, and it only takes a single wasp taking a bundle of Vespex to wipe out an entire nest.
‘‘It’s quite satisfying, in a weird way. You don’t often kill billions of pests in a single day,’’ Joice said.
The region is buzzing with honeybees and bumblebees already, and their populations will also benefit from the bait programme.
‘‘The meat base, the protein base, only wasps go for it, except for a few other things like blowflies. But not bees, which is the main thing. We’re always worried that people might make their own poison but use sugar, which attracts bees.’’
Joice said the Wasp Wipeout programme had been ‘‘one of the real success stories of the mainland islands’’.
For Nelsonians who want to get involved but don’t want to have to register for Vespex, the Brook Waimarama Sanctuary will begin baiting their 976 traps soon, and ranger Andrew Eastwood said they will need ‘‘quite a lot of people to help out’’.
About 20 volunteers, and sanctuary staff, put out the traps over the past few weeks, but since Vespex can’t be left out for more than eight days, Eastwood said more volunteers would be appreciated. ‘‘I’ve said it before, but once you’ve been [into the sanctuary] once, you want to go back. We’re already starting to see more birds, just the other day I was out and two robins came and were just playing right next to me.’’
The sanctuary will test wasp activity levels tomorrow, and Eastwood said, weather permitting, the baiting would begin the following weekend.