Feral cats (Felis catus) are among the most proficient and effective hunters in the world. In Aotearoa New Zealand (NZ), their skills are lethal to native species that have evolved without mammalian predators. Feral cats have been linked to significant biodiversity declines across the country. Cats are opportunistic predators that hunt ground-breeding species, like birds, bats, reptiles and even some insects- many of which are endemic.

Fig 1: It looks like siblings fighting over a small bird, a moment that captures the competitive behavior of feral cats (Image by- Gilbert Mercier, Flicker User
The extinctions of six endemic birds are linked to feral cats. Well-known cases include a single cat, Tibble, that caused the extinction of NZ’s only flightless song bird: Lyall’s Wren on Stephens Island. A single cat killed 120 endangered native short-tailed bats in one week on Mt. Ruapehu. Dotterel populations on Stewart Island, Grand and Otago skink populations in southern ANZ are at risk due to feral cats. The list of species pushed to the verge of extinction by cats is long and growing.
Yet despite their impact, feral cats are not currently included in NZ’s Predator Free 2050 campaign. This raises a major question: how is NZ tackling the feral cat problem?
With growing concern for native wildlife, the government has implemented several methods to eradicate or control cats: lethal baiting, trapping, shooting, and fencing. While putting these methods into action is necessary, it’s equally important to ask their effectiveness: Are they actually working? And how can we tell?

Fig 2: Feral cat awareness at Arthur’s Pass Wildlife Trust (Photo credit: Muhammad Waseem (used with permission)).
These were the very questions a group of researchers from Lincoln University set out to explore. Using camera traps, they conducted a study on Hawke’s Bay farmland to test whether trapping and shooting could effectively control feral cat population, and whether the area will be re-invaded over time, to measure the effectiveness of the method.
Forty motion-sensitive cameras stood beside the traps like sentinels, monitoring everything. Cats walked into the view, lured by rabbit meat and ferret scent. The cameras recorded activities before, during, and six months after the control operation. Before the operation 20 cats were detected. 17 feral cats were then removed (shot). The result? An 84% drop in both cat numbers and camera detections.
Aware of the risk of reinvasion, the researchers monitored the site again six months later- and detected only three new cats. The outcome was encouraging and demonstrated how proper methods combined with well-monitored action can make real difference. With the help of camera traps, the research could measure the effectiveness of the control operation and can suggest similar methods in areas facing feral cat issues.
Today, thanks to advanced technology like camera traps, monitoring has become much more efficient and convenient. This allows conservationists to evaluate their methodologies, observe activities remotely, and respond effectively.
How did cats become a serious ecological problem in NZ?
In my home country of Nepal, cats are seen as beloved pet and, traditionally, the guardians of grain stores, not as an ecological threat. As someone new to NZ conservation practice, I initially found the conservation method used in this study confronting. But the more I learned, the more curious I became: how did a country with no native mammalian predators come to see cats as such a serious problem?

Fig 3: Stray cat basking sun on Fairmaid Street, Lincoln (Photo: Author 04/01/2025)
Cats didn’t arrive in NZ until the mid-1800s. Earlier cats had visited along with Captain James Cook. His ship, plagued by rodents, carried cats as a solution to control pests and protect food supplies.
European settlers brought cats as companions. Some escaped or were abandoned, eventually forming a wild population. Ironically, many animals (and even people) arriving by ships ended up becoming invasive. Over time, their arrival became strongly linked with biodiversity loss.
Today the feral cats are officially recognised as invasive predators. They not only kill native wildlife but also spread disease. It is no coincidence that many native birds began to disappear after cats were introduced. In the NZ conservation story, it’s not unusual to say: “To solve one problem often means creating another!”.
Although some early impacts were noticed, such as the extinction of the Stephen Island wren, surprising these events were simply viewed with the mindset as nature improving, where invasive species were seen as improvement rather than threats.
Cats, whether brought to control rodents or to ease the settler’s solitude, may have served a short-term purpose, but over time introducing them proved to be a double-edged sword, causing severe harm to NZ’s native wildlife.
Learning this made me realize that today’s conservation challenges are deeply connected to historical choices!
Moving ahead
While we cannot re-write history, we can certainly learn from it!

Fig 4: Who decided which story to tell? The Great Hall stained-glass window at University of Canterbury made from 4,000 pieces of glass, showing Captain James Cook at number 19 (Photo: author 02/05/2025).
The journey of cats in NZ is a classic reminder of how small actions can have a large ecological impact. The feral cat issue isn’t just about one species nor is it the only invasive challenge NZ faces, it’s about how we approach conservation in a complex and ever-changing environment.
Looking back, we don’t know how much damage to NZ’s biodiversity could have been prevented or reduced if the scale of damage was understood earlier. As the country continues its battle against introduced species to conserve biodiversity through Predator Free 2050 campaign, integrating reliable monitoring tools like camera traps will be crucial in making informed and effective conservation decisions.
The author, Pareena Khadka, is a postgraduate student in the Master of Applied Science at Te Whare Wānaka o Aoraki Lincoln University. This article was written as an assessment for ECOL 608 Research Methods in Ecology.
Paper reference: Nichols, M., Glen, A. S., Ross, J., Gormley, A. M., & Garvey, P. M. (2023). Evaluating the effectiveness of a feral cat control operation using camera traps. New Zealand Journal of Ecology, 47(1), Article 3501. https://dx.doi.org/10.20417/nzjecol.47.3501







































