Predator Free Wellington has applied to use what's been described as an inhumane type of trap in the struggle to eradicate the final rats on Miramar Peninsula, which remain elusive.
Glue board traps are described by animal welfare groups as inhumane and one of the cruellest methods of killing animals.
Animals that come into contact with the sticky adhesive board are caught and become stuck. They can suffer a slow death by starvation or suffocation.
The sale and use of glue board traps was prohibited by the Ministry for Primary Industries (MPI) in 2015, sending a clear message these traps were no longer acceptable from an animal welfare perspective.
There were concerns about the pain and distress the traps caused captured rodents – including the length of time they may be left on the traps and the potential for inhumane disposal.
However, exemptions to the ban can be obtained with MPI approval. Predator Free Wellington wants to use them to get rid of ship rats.
Predator Free Wellington's original goal was to declare Miramar Peninsula predator free by 2020.
Almost two years on, the project's 2020/21 Impact Report said Norway rats and weasels have been completely eradicated, but there remained a small number of ship rats.
Rat activity has been detected in steep and weedy areas where access is difficult.
"Getting to really low rat numbers means the textbook for trapping rats gets thrown out, and we are literally catering to individual preferences", the report said.
Predator Free Wellington project lead John Hambidge said they have spent many hours viewing the behaviour of rats via night vision trail cameras.
"This has shown that there are certain rats that do not enter any of our eradication devices, no matter the length of time we view them or the presentation of the trap or bait station."
Hambidge said glue boards would be another tool to help eradicate the elusive rats.
"In the right environment under the right circumstances these traps could be used to eradicate these animals as they require minimal interaction by the animal to work."
He said glue boards would be used sparingly and with care.
"We understand that this type of trap needs to be treated with great respect.
"Should we use a glue board we would place the device out on dusk and collect first thing the following morning to coincide with a rats active period and other non-target animals' resting period."
MPI animal health & welfare acting director Stephen Cobb confirmed the ministry has received an application to use glue board traps on Miramar Peninsula.
The application is currently being considered and there was no timeframe on when a decision was likely, Cobb said.
Approvals can be granted when it is in the public interest and there is no viable alternative.
They are subject to several conditions relevant to each case including restrictions on who can use the traps and where as well as euthanising trapped rodents, ensuring death prior to disposal.
Since 2015, MPI has issued 54 approvals for glue board traps to be used across the country.
Predator Free Wellington project director James Willcocks said they were "really close" to declaring the peninsula predator free.
"We started out with the best endeavours to be done within that original time frame. Our journey is akin from being babies in nappies really, to grizzled old campaigners.
"We have just learnt so much and we've had to forge into this new space where no one has been before and it has been really, really hard."
But just because the project has failed to meet its original target of eradicating predators on the peninsula by 2020, efforts to date have made a difference.
Predator Free Wellington's latest impact report said native birds have increased by a third and wētā numbers have doubled.
"We're so lucky that we're already getting this amazing pay back in terms of ecological resilience and native species returning, that just helps reinforce the commitment to get to the end", Willcocks said.
"We've now got records of Kākā on the peninsula, of Kākāriki, of people telling us they're seeing Pīwakawaka in their back yard for the first time in 30 years, hearing Ruru at night."