‘Spy’ wallabies to be used in control bid

A wallaby is fitted with a collar the same as those being used in a new trial programme to find...
A wallaby is fitted with a collar the same as those being used in a new trial programme to find groups of wallabies in the South. PHOTO: MANAAKI WHENUA LANDCARE RESEARCH
Satellite tracking of collared wallabies could be used to seek and destroy groups of the introduced, unwanted pests in the South.

Otago Regional Council national programmes project delivery specialist Gavin Udy said the council was working with Environment Canterbury and the Ministry for Primary Industries’ Tipu Mātoro National Wallaby Eradication Programme to investigate how useful "spy" wallabies could be to control Bennett’s wallabies in areas where they were found in low densities.

Starting this month, 10 collared wallabies would be released into their feral range in South Canterbury to be tracked using a helicopter-based hunting team, using thermal imaging, he said.

The "moderately gregarious" animals could be found in small family groups and would congregate to feed.

And if a satellite-tagged animal did lead the hunters to a group of wallabies, only the spy wallaby would be spared, Mr Udy said.

"The technique relies upon a tagged animal that can be tracked via a satellite transmitter and lead control operators to other individuals of the same species that are then controlled," he said.

"Any non-tagged wallabies found will then be shot, leaving the satellite tagged wallaby to continue to seek out more wallabies.

"If successful, applying this technique in areas of very low or low wallaby density has the potential to increase detection rates and kill rates and accelerate the eradication of Bennett’s wallaby.

"Finding wallabies across large landscapes and difficult terrain is resource hungry, where there are so few wallabies present.

"A small breeding population can grow and expand over time.

"It is critical that we develop new cost-effective tools to find wallabies in these environments."

The council has a goal of eradicating the introduced marsupial in Otago by 2029.

Over the last financial year searches were conducted over 332,500ha and 16 wallabies were destroyed.

Mr Udy said despite a "containment area" of 900,000ha in South Canterbury, the animals’ feral range was considered to be 2,500,000ha across parts of South Canterbury and Otago, including the containment area.

In some areas where the pest animals were found more than 100 wallabies could be found per square kilometre.

However, in other areas within their range there were fewer than 0.1 wallabies per square kilometre, he said.

At present, all satellite-tagged wallabies were being held in a captive-animal facility near Christchurch.

They would be taken to different parts of South Canterbury by road, where a helicopter would take the collared animals to their release locations in the Mackenzie and Waitaki districts.

A satellite-tracked animal could be followed for up to a year after it was released back into the wild, Mr Udy said.

The work was being conducted under approved permits from the Ministry for Primary Industries and the Animal Ethics Committee of Lincoln University.

Permission had also been granted by landowners to release the wallabies, Mr Udy said.

The council had invested $110,000 over two years in the fieldwork component of the investigation, "the potential benefits of which will far exceed the costs of the level of investment made in terms of protecting Otago from wallaby spread and the damage they do to native bush, farms, crops, commercial forestry and our biodiversity".

The national eradication programme had contributed $100,000.

Environment Canterbury was supporting the programme through landowner consultation, DNA sampling and supplementary control work, Mr Udy said.