One Cat, 95 Nests, Zero Left: How A Single Feral Cat Destroyed An Entire Endangered Bird Colony

Trail camera captures the 6kg feral tom in the act - preying on black-fronted tern chicks at the Waiau Toa colony. Photo: Department of Conservation

One cat. Ninety-five nests. An entire breeding colony of endangered black-fronted terns - wiped out over a single weekend.

In December 2024, a lone 6-kilogram feral tom reached an island in the Waiau Toa/Clarence River system in Canterbury, New Zealand. What followed was a massacre. The cat systematically destroyed every nest in the colony - killing adults, chicks, and eggs across all 95 nests. The local population collapsed from roughly 180 birds to just 20.

The black-fronted tern, known as tarapirohe in te reo Maori, is classified as Threatened - Nationally Endangered. Only 5,000 to 10,000 remain in the wild. This single cat, in a single weekend, may have erased decades of conservation work on this stretch of river.

A Year-Long Hunt​

Department of Conservation rangers knew the cat was out there. They deployed over 700 kill traps. The cat ignored all of them.

Contractors Jasen and Shannon Mears were brought in. They tracked the animal for months. It was trap-shy - at one point it was caught and escaped. Their dog eventually picked up the scent near the Acheron campsite in late November 2025, and the cat was finally taken using leg-hold traps baited with whole rabbits. Eleven feral cats total were removed from the area during the operation.

Aftermath: a dead tern, one of many killed by the feral cat. Photo: Department of Conservation

Stone Cold Killers​

On November 21, 2025, New Zealand Conservation Minister Tama Potaka announced that feral cats would be added to the Predator Free 2050 eradication strategy - joining rats, possums, and mustelids on the national kill list. He called feral cats "stone cold killers."

The numbers back him up. New Zealand has an estimated 2.4 million feral cats. Over 90 percent of the 3,400 public submissions on the proposal supported their inclusion. This was not close.

In the weeks before the announcement, feral cats had also been caught killing over 100 short-tailed bats in one week near Ohakune, and driving the southern dotterel toward extinction on Stewart Island.

Full DOC media release on the captured cat

RNZ in-depth: Feral cats added to Predator Free 2050

The Pattern​

This is what a single feral cat does when it reaches an isolated colony. Not a pack. Not a coordinated effort. One animal, acting on instinct, unraveling conservation programs that took years to build.

Cat advocates love to say outdoor cats are "part of the ecosystem." New Zealand is learning, the hard way, what that actually means. The ecosystem cannot afford them.

A black-fronted tern family - the kind of scene the Waiau Toa colony may not see again for years. Photo: Department of Conservation

The 206 nests recorded across six monitored colonies this season now have a better chance. But the terns at Waiau Toa are functionally gone. It will take years - if the colony recovers at all.

One cat did that.

 

[barncat_dad]

Well I'll say this; one cat doing all that is hard to wrap your head around but then I think about my old feral's and how they use to bring stuff to the porch every single night. Mice, birds, moles, you name it. Multiply that by a colony of 20 or 30 and yeah I can see how a whole nesting area goes down fast.

What gets me is 700 traps and the thing dodged all of them. That's not luck that's a smart cat. Whole rabbits as bait is a new one on me though; guess the standard stuff wasn't cutting it.

I don't know about eradicating 2.4 million of them though. That's a number you say and then what. How do you actually do that across a whole country.

 

[prairie_cats]

I don't know about eradicating 2.4 million of them though. That's a number you say and then what. How do you actually do that across a whole country.

New Zealand has been doing predator eradication for decades now and they are actually good at it. They cleared entire islands of rats using aerial poison drops, same with possums. It is slow but they have the infrastructure and the political will which is the part most countries are missing.

The difference with cats is that people get emotional about them in a way nobody does about rats. That is the real barrier not the logistics.

As for the trapping honestly 700 traps sounds like a lot but if they were all standard DOC200 box traps then a smart cat would learn to avoid them fast. Cats are not like stoats they don't just walk into a box. The whole rabbit bait makes sense because it is something the cat would actually investigate rather than just walk past.

I lost a cat to a coyote on my acreage and that was one predator doing one thing. Reading about a single cat wiping out 95 nests in a weekend just reinforces what I already knew. Cats are insanely efficient killers and most people have no idea.