New Thinking

FARMERS WEEKLY – farmersweekly.co.nz – January 24, 2022 19

Smart way to track pests

A Northland man is carrying on his father’s legacy of conservation by keeping predators under control. Hugh Stringleman caught up with Gotcha Traps’ Marcus Agnew.

PEST control of rodents and mustelids needs a monitoring system devised and there’s one sold here and around the world by Gotcha Traps called Black Trakka.

Lures and pre-inked tracking cards are placed inside light and very portable tunnels to show what pests are active and where to place traps effectively.

Black Trakka will also show the presence of desirable species like gecko and wētā, building a picture of biodiversity and restoration.

Gotcha Traps principal Marcus Agnew says pest management is then more efficient and targeted, making sure expenditure can be analysed and justified.

Relatively new to the job and recently relocated from Hawke’s Bay to Northland, Agnew is carrying on the business founded by his late father Warren, a passionate conservationist and Black Trakka inventor.

Systematic tracking of smaller pest species is an essential element of control programmes funded and delivered by the Department of Conservation (DoC), wildlife sanctuaries, predator-free islands and landcare groups.

It is also being introduced to conservation programmes run by schools and universities and in consent applications and regeneration reports by land developers.

There is an increasing interest coming from farming groups, as they look to get more involved in pest control and to demonstrate their sustainable and vermin-free practices to other stakeholders.

Orchards are another potential site, with research overseas using inked tracking cards to establish the numbers of rats in orchards and the effectiveness of their pest control, with a move toward accreditation requirements in areas of food production.

One tunnel, or several randomly scattered, will not provide a systematic picture of the vermin problem.

Mustelids like stoats and weasels, if controlled, may leave room for rats and mice to flourish.

There are protocols for tunnel placement, spacing and card reading and refreshing, developed by conservation scientists.

In the biggest and most ambitious conservation schemes, like Sanctuary Mountain: Maungatautari, hundreds of Black Trakka tunnels are used along more than 20 north-south grid lines as long as 1km at 50m intervals.

The monitoring shows continued freedom from excluded rats, stoats, ferrets and weasels, but not yet mice.

An example of where the tunnels are being used to excite interest and action in pest management is the Ruamahanga Restoration Trust in Wairarapa and its programme called Schools Behind Our River.

Trustee Campbell McLean says sponsors and partners have put together $1000 predator kits for schools for the purposes of tracking and trapping.

“Tracking sparks the curiosity of children to be like detectives, using the Gotcha Trap booklets of the feet patterns of different species,” McLean said.

“Some will get into the monitoring and data collection side, others into trapping.

“It gets schools participating in the Predator-Free NZ process without incurring additional costs.”

Another example of the Black Trakka effectiveness has been on Gough Island in the South Atlantic where the Royal Society for the Protection of Birds has been waging war on mice.

Over two million seabird chicks are lost every year, pushing some species towards extinction.

Albatross chicks can be attacked and eaten in the nest while their parents are away.

Agnew says tracking cards and monitoring provides feedback to RSPB sponsors, reassuring them that mice are being controlled and chicks saved.

Exporting to Europe, the Caribbean, Hawaiian Islands and US Virgin Islands has put him in touch with control systems for pests not found here, like mongoose.

Although the Back Trakka components are not expensive, a common question for Agnew is, “Why not go straight to trapping?”.

Without pre- and postmonitoring of the pest species, trapping could end up as harvesting a self-replacing animal that persists in numbers to threaten native species like birds and lizards.

“You need to know what the infestation level is and, afterwards, how many are left out there,” Agnew said.

“In mainland sites we may be aiming for suppression of rats, say below 5%, whereas on island sanctuaries every last one must be killed.”

Warren designed and perfected the tunnels and tracking cards, making what appears to be a straightforward monitoring system – weather-proof, reliable, portable, reusable and recyclable.

The lightweight polypropylene tunnels come flat for backpacking and are quickly assembled and anchored with two wire staples.

The pre-inked cards are unfolded and placed lengthwise down the tunnels, with speciesappropriate lures in the middle.

Pests stand on the inked sections to eat and then retreat across the white absorbent endsections of the cards, making their distinctive tracks.

The ink doesn’t wash out or dry out and the tracks don’t fade or disappear before they are read and cards replaced.

It is non-toxic and sensitive to treasured species, and is the right viscosity to leave footprints, but not too sticky to trap insects.

The standard tunnel is 500mm long and 100mm wide and high, and costs $12.65 plus GST, while the cards are $1.65 each.

They are very light and portable, able to be carried long distances before on-the-spot assembly.

Alternative tunnels are either much heavier (wood) or are made from corflute, which lingers in the environment as it breaks down.

Warren worked through all the stages of development, including ink-it-yourself options, taking feedback from rangers and receiving encouragement and financial assistance from the DoC.

Former teacher Warren and his wife Lois also developed a native bird centre on the Mahurangi river, near Warkworth.

POPULAR: The basics of Black Trakka are increasingly used in pest management, vendor Marcus Agnew says.

Keep an eye out

The latest issue of Dairy Farmer will hit letterboxes on January 31.

Our OnFarmStory this month features a Waikato farmer who is benefi ting from his late father’s vision. We also catch up with Bay of Plenty farmers who focus on environmental issues and meet the man behind the rapid expansion at Dairyworks.

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