The Rat Eradication Roadmap

Removing rats from Waiheke Island requires a long-term vision and extensive research into how, and if, it is possible from a technical, cost, and social point of view. The project is split into five main phases.

(use dark green arrow device as phase headings to connect section to the diagram above ?)

Phase 1 (2022–2025): Trials & Research

Rationale

Waiheke Island (population 9,400; 92 km²) presents a distinct challenge for rat eradication due to its varied terrain and land use. Techniques for removing rats from rural settings like forests and open land are well established, but strategies for urban environments are less developed.

Social and economic research plays a vital role by enriching the trials, offering a deeper understanding of both the island and its community.

Key Objectives

Test eradication tools and methods in different environments
Understand community attitudes and concerns
Evaluate the cost-effectiveness of island-wide eradication

Insights so far

i) Urban Rat Trials

🧪 Technical

Location	Key Questions		Key Findings
Kennedy Point (2022)	Can traps alone remove rats?	Traps help control but can’t fully eradicate.
Ostend (2022)	Can bait stations remove rats in commercial areas?	Weekly serviced 25x25m bait station grids are effective.
Mangroves	Can floating bait stations work?	Yes, specially designed stations are effective.
Oneroa (2023)	Can bait stations work in residential areas?	Yes, but need multiple tools and intensive effort.
Surfdale (2024)	Can methods be refined and confirmed?	Success depends on reducing alternative food sources, using multiple tools, and intensive monitoring.

Preliminary Rural Trials (Planned 2025) - move this section below Economic Research

Test bait distribution via hand and drone methods to :-
- Determine optimal bait quantity
Assess impacts on non-target species

💬 Social Research

Focus	Key Insights
Community Support	98% of residents support rat eradication.
Concerns	Mixed views on toxins and ecological impact.
Dog Owners	Mostly supportive if bait is used responsibly.
Boaties	Small boats pose a higher reinvasion risk; most clean regularly and could detect rats early.

💰 Economic Research

Question	Findings
Are the benefits greater than the costs?	Yes – projected $249.9M net benefit over 50 years.
Estimated Costs	$43M for eradication + $72.9M total with biosecurity over 50 years.
Key Benefits	• Doubling of bird populations • Boost to ecotourism ($20.1M value) • Increased agriculture productivity ($26.7M) • Saved pest control costs ($22.1M)