The takahë is the largest living member of the rail family. It is flightless and occurs only in New Zealand. Two different species existed historically: one on the South Island, Porphyrio hochstetteri, and a second on the North Island, P. mantelli.
A combination of hunting, habitat destruction, and introduced predators reduced the range of both species dramatically, and by the early part of the 20th century, they were considered extinct.
A small population of 250 – 300 birds was rediscovered in a remote region of the South Island in 1948.
The Situation
By 2014, an estimated 246 takahë (Porphyrio hochstetteri) remained in existence: 166 occupying eight protected release sites and seven captive facilities, and approximately 80 birds populating one wild site in the Murchison Mountains. The Takahë Recovery Group invited CPSG to collaborate on developing a plan for the management of remaining takahë as two distinct meta-populations: one focused on the northern islands and the other on southern areas. This approach would foster adaptation in two contrasting bioclimatic zones, substantially reducing the need for long-distance translocation of birds and eventually replacing the now extinct North Island takahë, Porphyrio mantelli, with an ecological equivalent.
The Process
CPSG worked with collaborators to develop goals for meta-population management, formulate broad strategies for managing risk and improving population performance, and determine optimal breeding and transfer recommendations for 2014-2015. The final plan considered the founding, growth, and capacity phases of the proposed North Island meta-population and the requirements for demographic and genetic viability. It allows for ongoing support to the South Island population as needed. Protocols for data management, annual program review, and revision are also included.
The Results
The meta-population plan has been endorsed and its implementation is underway, coordinated through the Takahë Recovery Group. A first-year review is scheduled for late 2015. This project is notable because it draws together the management of several discrete island populations of birds under a single umbrella of demographic and genetic management, using tools and techniques designed for zoo populations. To encourage sustainability, it advocates a staged progression from high to low intensity management once specific population viability milestones are reached. This creative approach may provide a useful model for other New Zealand species, many of which are relegated to island refuges to escape mainland threats from introduced predators.