The recent success story of the Southern New Zealand dotterel, or pukunui, on Stewart Island is a fascinating glimpse into the complex world of conservation efforts. This bird species, unique to the island, has been teetering on the edge of extinction, with feral cats posing a significant threat. However, a controversial decision to use 1080 poison has led to a remarkable population boost, offering a glimmer of hope for their survival.
The Impact of Feral Cats
Feral cats have been a persistent problem for the pukunui, with an estimated 40-50 adult birds falling victim to these predators each year. This relentless predation has pushed the species towards extinction, highlighting the delicate balance of ecosystems and the impact of invasive species. The situation was dire, and something had to be done to protect these vulnerable birds.
A Controversial Solution
The decision to use 1080 poison was met with opposition, as it is a highly controversial method. However, the results speak for themselves. The aerial drop of 1080, a collaborative effort between DOC and Zero Invasive Predators, has led to a remarkable 52% increase in the pukunui population. From 105 birds, the population has grown to 160, the largest increase since recovery efforts began over three decades ago. This success is a testament to the effectiveness of this approach, despite its controversial nature.
The Secondary Kill Strategy
The strategy employed was a 'secondary kill' approach, targeting not just the cats but also the rats that cats prey upon. Cats don't consume the 1080 cereal baits, but rats do, and by reducing the rat population, the cats' food source was diminished. This clever strategy proved successful, with feral cat numbers reduced to very low levels in the operational area. The protection of adult birds during nesting and chick-rearing was a critical factor in the population boost.
A Delicate Balance
While the results are encouraging, the battle is far from over. Feral cats are resilient and have been detected at the edges of the operational area, and they remain a threat to breeding sites elsewhere on the island. The pukunui are not yet safe, and continued action is necessary to ensure their long-term survival. This highlights the ongoing nature of conservation efforts and the need for constant vigilance.
Broader Implications
The success of this conservation effort has wider implications. It showcases the potential for innovative strategies to protect vulnerable species and the importance of collaboration between organizations. Additionally, it raises questions about the role of invasive species and the delicate balance of ecosystems. The impact of feral cats on the pukunui population is a stark reminder of the interconnectedness of nature and the need for proactive conservation measures.
A Step Towards Restoration
The ultimate goal is to increase the pukunui population to 300 by 2035, a target that now seems within reach. This success story is a step towards restoring the mauri of Rakiura and creating a safe haven for other taonga species like kākāpō and tīeke. It's a testament to the dedication and expertise of conservationists and a glimmer of hope for the future of these unique and precious bird species.
Conclusion
The controversial 1080 drop on Stewart Island has sparked a fascinating debate and offers a unique insight into the world of conservation. While the results are promising, the ongoing battle against invasive species and the need for constant adaptation and innovation are clear. This story serves as a reminder of the importance of protecting our natural heritage and the delicate balance of our ecosystems.
