To prevent this from happening, the Otago Regional Council and Environment Canterbury are asking the public to report any sightings of wallabies outside the Canterbury containment area.
As part of efforts to control the spread, considered a pest under both councils’ regional pest management plans, new signs have been erected along the Canterbury and Otago borders, encouraging anyone who has seen a wallaby to report their sighting to the national website reportwallabies.nz. Sightings would be investigated by the relevant council, and a follow-up search of the area would be undertaken by contractors.
While the Bennett's wallaby remains in a 900,000ha containment area in South Canterbury, where populations were established for recreational hunting in the 1870s, the animals have been steadily increasing in density and geographic range. Outside the containment area, which is centred in the Hunter Hills, and includes the Two Thumb, Kirkliston and Grampian ranges, wallabies have been found as far north as Marlborough and as far south as Flagstaff, and are also known to be in the Mackenzie and Lake Hawea areas.
Environment Canterbury wallaby programme leader Brent Glentworth said the signs had been placed in key high traffic areas surrounding the containment area to target travellers who may not be aware of the wallaby’s pest status.
"As well as looking out for the animals themselves, anyone out and about is also encouraged to look for signs of wallabies such as footprints or droppings," Mr Glentworth said.
The two councils are working together as part of the $27million national wallaby eradication programme, aimed at reducing and containing populations of wallabies, boosting regional employment opportunities, delivering environmental and economic benefits.
In Otago, all efforts are focused on eradication in the medium term. For this to work, the ORC is heavily reliant on the public to report sightings.
Since 2016, the ORC had received about 30 to 40 reports of wallaby sightings each year. In February, regional councillor Kevin Malcolm told the Oamaru Mail recent sightings had been reported in the Trotters Gorge, Dip Creek, Hilderthorpe, Richmond and Ngapara areas.
ORC environmental implementation manager Andrea Howard said reported sightings enabled contract teams to search and destroy wallabies, to prevent breeding populations from establishing in Otago.
"Wallabies compete with livestock with three wallabies eating as much as one sheep," Ms Howard said.
"They can foul pasture, damage fences, destroy agricultural crops, contribute to erosion and kill plantation forest seedlings. Wallabies also stop native bush regeneration by depleting forest understoreys."
A female wallaby can have one joey developing in her pouch while also carrying another fertilised embryo on hold until the joey is no longer dependent on her. This means that a single female could stem a breeding population.
