Sixteen tītī/sooty shearwater chicks, out of 21, were discovered dead recently at Irahuka Long Point in the Catlins.
Examination of trail camera footage revealed a lone ferret was the culprit, decapitating some defenceless chicks and leaving others with fatal bite wounds to the neck.
Francesca Cunninghame of Forest & Bird visited the seabird colony twice last week to check on the chicks, which were due to fledge in a matter of weeks.
“It’s grim, very sad news,” says Cunninghame. “The chicks have been sitting in their burrows since they were laid as eggs way back in December. They were all in good condition, too.”
The colony is located on a reserve owned by the Yellow Eyed Penguin Trust, where Forest & Bird volunteers assist with predator control. Since 2017, the volunteers have increased monitoring of the tītī colony as part of Forest & Bird Dunedin branch’s ‘Bring back the seabirds’ project.
This incident is a devastating blow to the hard work of volunteers, but one they are all too familiar with: a ferret wiped out all the chicks in another tītī colony on the Otago Peninsula in 2019.
These attacks highlight both the damage that can be dealt by a single trap-shy predator and the limitations of ground-based predator control.
“Working together with field rangers from the Yellow Eyed Penguin Trust, we’re funding extra trapping with enticing ferret-attractive baits. We really hope we can catch the killer so some of the tītī can survive to fledging,” says Cunninghame.
Trail camera footage also revealed a feral cat in the seabird colony, which has since been captured. “We recorded the cat sniffing at burrows. This was a worry, because the chicks are starting to emerge from their burrows and sit on the surface, making easy pickings for a cat,” says Cunninghame. “We’re relieved it's no longer a threat to the remaining chicks.”
Tītī, also known as sooty shearwaters, are classified as ‘At risk – Declining'. The colony at Irahuka is a remnant of a massive population that once occupied suitable habitat on mainland coastlines but is now mostly confined to offshore islands. The colony is on a reserve that also supports breeding pairs of endangered hoiho yellow-eyed penguins.
New Zealand is the seabird capital of the world, but suitable breeding sites for most of our seabird species remain only on offshore islands, after introduced predators and changing land use decimated mainland populations.
“If we want our spectacular seabirds like tītī to return to the mainland, we need more than just volunteer-maintained traplines,” says Forest & Bird spokesperson Nicky Snoyink.
“Likewise, if we want to achieve Predator Free 2050, successfully implement the national biodiversity strategy Te Mana o te Taiao and tackle the biodiversity crisis, we need to get serious about properly resourcing predator control – including landscape-scale solutions and innovation.
“We also need to consider pests not covered by Predator Free 2050, like feral cats, which pose a significant threat to wildlife.
“The National Plan of Action for Seabirds 2020 focuses on protecting seabirds from fishing-related mortality at sea, but we need to protect them on land too. This means we need Government support for effective and broad-scale control that addresses all predator threats.”