In order to understand whether and if so which predators were contributing to an apparent decline in the numbers of Fiordland crested penguins, the West Coast Penguin Trust embarked on a four year study using trail cameras in 2014.
For the 2019 season, which followed a ‘mega-mast’ seed event and predicted rat and subsequently stoat population explosions, the Trust established an annual breeding success monitoring programme.
In 2020, following a mega mast in Autumn 2019, the Trust has extended the project, with the support of Wellington Zoo and the Birds New Zealand Research Fund, with the aim of better understanding whether breeding success is adversely affected by the presence of stoats, and if so, what is the best means to manage that threat.
An overview of the work planned for the 2020 season is available on the Birds NZ website.
The Trust’s Tawaki Ranger and Trustee, Robin Long, gave this TED type talk in Franz Josef in October 2019, summing up the Trust’s work and her experience of tawaki both at home in Gorge River and volunteering with The Tawaki Project.
The Fiordland crested penguin, or tawaki, is in need of our help, being listed as Nationally Vulnerable and one of the least studied and rarest penguins.
Tawaki is the only crested penguin to inhabit the main islands and coasts of New Zealand. The 2012 IUCN red list classifies them as Vulnerable.
The West Coast Penguin Trust ensures that conservation management is based on good science.
The Trust has set out to establish which predators may be contributing to a decline in the population so that appropriate targeted action can be taken. This follows a technical review of the conservation status of both the species and earlier management actions and a priority action was to determine the effects of introduced predators on the breeding success of tawaki.
A funding bid for a pre-predator control project to the Department of Conservation in 2014 was successful and motion activated cameras were purchased with sponsorship from local businessman, Geoff Robson of Greenstone Helicopters.
Cameras are a low impact method of obtaining the information and these were installed at two colonies at Jackson Head and Gorge River in South Westland, in late August for the four breeding seasons 2014-2017.
This work will ensure that any predator control targets the appropriate species in the most effective way, thus saving money and contributing to the conservation of the species in the longer term.
Our study coincided with a five-year study into the ecology and particularly the foraging ecology of tawaki by Dr Thomas Mattern and The Tawaki Project. We were able to share both resources and findings and the projects complemented each other extremely well at the Jackson Head site.
In the second year of the study, 2015, El Niño conditions off the West Coast resulted in almost complete nest failure at Jackson Head as chicks starved and adults swam up to 100km for little food and poor nutrition.
In the third year, 2016, stoats, which had been scarce, appeared in large number at the Jackson Head site and both eggs and chicks were lost to predation.
A fourth year in 2017 found breeding back to ‘normal’ levels, without El Niño conditions and with barely any stoats visible on camera footage.
With two abnormal years in the four-year study, but it appears that the large numbers of stoats and the loss of chicks was a direct result of an earlier beech seed mast event close by. These events, when trees produce massive amounts of seed every 2- 6 years, result in explosions in mice and rat populations, followed by stoats. As the food source for stoats runs out – as the seeds rot and germinate and rodent numbers reduce – stoats are likely to spread out in search of food. We believe they spread to Jackson Head in 2016.
The report at the end of the fourth year is here: WCPT Tawaki report 2018 Final
What happens next
The Trust has shared its findings with the Department of Conservation and is recommending that landscape predator control operations be managed to take tawaki into account. They have traditionally been focused on species such as kaka and mohua, and ensuring tawaki nesting areas are included is a tiny step to take as treatment areas are already including or could include such colonies.
In order to gain a better understanding of the situation, the Trust started a breeding success survey of nests in the three areas of our study in the 2019 season and, in addition for the 2020 season, will be doing trail camera and tracking tunnel monitoring (overview here).
A variety of both research and management priorities have been identified for tawaki and it’s likely that the West Coast Penguin Trust will be involved in progressing those priorities for the benefit of the species, working with both the NZ Penguin Initiative and The Tawaki Project. Have a look at The Tawaki Project site for up to date blogs and news of their project, now focused in Milford Sound.
In addition, our Trustee and tawaki ranger, Robin Long, continues her volunteer tawaki survey work. This year, 2020, she will be surveying the south eastern coast of Stewart Island after covering the north western coast last year.