A black-fronted tern family. Photo / Department of Conservation
A year after a single feral cat destroyed a large black-fronted tern/tarapirohe colony on Canterbury’s Waiau Toa/Clarence River, it has finally been caught.
In December 2024, the feral tomcat reached a large island in the river where the endangered terns were nesting.
It killed and ate several adult birds, chicks and eggs, disturbing the colony and causing almost all 95 nests to be abandoned.
Last week, contractors, husband and wife team Jasen and Shannon Mears, of J & S Mears, were carrying out a leg-hold trapping operation, targeting feral cats to protect nesting tarapirohe from predators.
They caught 11 feral cats, including the 6kg feline responsible for last year’s colony attack.
But it wasn’t easy.
Shannon Mears said they tracked the large feral tomcat – identified by its long stride and distinctive prints – for three days, before finally luring and trapping it.
“It took three nights to catch it,” she said.
“Each morning, we would find the cat had yet again evaded or ignored traps and bait.”
Mears said the cat’s prints clearly showed him visiting the river to check the water level near the same tern colony he attacked last year.
“It would have only been a matter of time before the river level dropped, and he would have been able to reach the colony again.
“We went to great lengths to lure it with whole rabbits as decoys, wing traps and buried leg-hold traps covered by tissue paper and soil, in which it was eventually caught.
“Even then, it managed to pull the stake out and hide in a den about 200m away in the middle of the Acheron campsite, where our dog, Billy, tracked him.”
Shannon said it was challenging to outsmart the wily and trap-shy cat, which had carefully avoided the many leg-hold traps set around the colony and network of over 700 kill traps in the wider area.
“It was a relief to finally catch it and a win for the black-fronted terns, which will be a lot safer this breeding season,” Mears said.
DoC South Marlborough principal ranger Pat Crowe said after the devastating loss of the colony last year, it was good news to see the results of the massive trapping effort.
“It was sad to see the impact a single cat had on an entire colony of these special birds when everyone was working so hard to protect them,” Crowe said.
“So, it’s gratifying it has now been removed along with 10 other feral cats.
“Controlling predators like feral cats, ferrets and stoats is difficult work, especially when you’re dealing with trap-shy individuals, but it’s critical to give species like tarapirohe and other braided river birds a fighting chance.”
Crowe said apart from a flooding event in late October, which disrupted early nesting, it had been a successful breeding season with no signs of predation by introduced predators within the trapping area.
The Waiau Toa/Clarence River is an important habitat for black-fronted terns.
At least 12 colonies are nesting on islands in the braided river this year, and 206 nests have been recorded in the six monitored colonies.
Crowe said people could do their bit to help protect the tern colonies when they’re out naturing in the Molesworth Recreation Reserve, by giving the birds space and keeping out of the nesting colonies.
People who spot a feral cat while out driving or walking in this area are encouraged to contact the DoC Renwick office at renwick@doc.govt.nz.
Predator control, island enhancement for nesting, and bird monitoring have been undertaken in the area for about a decade.
The project is supported by Ngāti Kurī and funded by Canterbury Regional Council (Environment Canterbury), DoC and Toitū Te Whenua Land Information New Zealand (Linz).
Much of the work is carried out by J & S Mears Contracting and Wildlife Management International Limited, which monitors the birds.
- Content supplied by the Department of Conservation.