Feral cat preys on black-fronted tern chicks in December 2024. Photo: DOC
A feral cat that destroyed a large black-fronted tern colony on Canterbury's Waiau Toa/Clarence River has finally been caught.
The tom cat killed and ate several adult tern, chicks and eggs, resulting in birds abandoning almost all 95 nests on an island in the river last December.
Black-fronted terns or tarapirohe are endangered with an estimated population of less than 10,000 birds and declining.
Last week contractors Jasen and Shannon Mears of J & S Mears carried out a leg-hold trapping operation in the Clarence River area, targeting feral cats to protect nesting tarapirohe from predators.
They caught 11 cats, including the 6kg tom cat responsible for last year's colony attack.
Shannon Mears said the large feral tom cat - identified by its long stride and distinctive prints - was tracked for several days before they were able to successfully lure and trap it.
Three large tom cats were caught in the vicinity of the black-fronted tern colonies in December 2025. Photo: J&S Mears
The wily cat had carefully avoided the many leg-hold traps set around the colony and a network of more than 700 kill traps in the wider area, she said.
"It took three nights to catch it. Each morning, we would find the cat had yet again evaded or ignored traps and bait. Its prints clearly showed him visiting the river near the same tern colony he decimated last year to check the water level. 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," she said.
The couple 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. The cat was eventually caught in a leg trap.
Black-fronted tern killed in a feral cat attack in December 2024. Photo: DOC
"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," she said.
Earlier this month feral cats were added to the Department of Conservation's Predator Free 2050 list. There are an estimated 2.4 million feral cats in New Zealand compared to 1.2 million pet cats and about 200,000 stray cats, although the exact numbers are not known.
Feral cats are apex predators, which have been linked to the extinction of several native bird species. They also hunt bats, lizards, frogs and even insects such as wētā.
Department of Conservation South Marlborough principal ranger Pat Crowe was pleased with the results of the trapping after last year's colony loss.
Black-fronted tern family. Photo: DOC
"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," he said.
Apart from flooding in late October that disrupted early nesting, he said it had been a successful breeding season with no signs of predation by introduced predators in the trapping area.
The Waiau Toa/Clarence River is an important habitat for black-fronted terns. There are at least 12 colonies nesting on islands in the braided river this year and 206 nests have been recorded in the six monitored colonies.
People could help protect tern colonies in the Molesworth Recreation Reserve by giving the birds space and keeping out of the nesting colonies, DOC said.
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