New Trust Aims to Help the Blue Duck

Forest and Bird, Issue 307, 1 February 2003, Page 4

New Trust Aims to Help the Blue Duck

is chairman of the

Trust, representing Forest and Bird, with two DoC conservators, a representative of Genesis Power, and an independent scientist.

KEITH CHAPPLE

he future of the blue ac duck — also known as whio — may be brighter as a result of a project designed to create new populations of this ‘whitewater’ specialist. The IUCN Red Data Book recently raised the status of blue duck from ‘threatened’ to ‘endangered’. With about 2500 birds remaining, the blue duck is much rarer than the kiwi and more difficult to save. Unlike most endangered species, which can be ‘saved’ on predator-free offshore islands or in managed and fenced sanctuaries, blue duck recovery operations can only take place in the duck’s habitat — wild white-water streams and rivers. Blue duck are peculiar to New Zealand and, as torrent

ducks, specifically adapted for life on clean, fast-flowing rivers and streams. While numbers are low, the birds are reasonably widespread with strongholds in the central North Island, Kahurangi National Park, South Westland and Fiordland. Predation, principally by stoats, is thought to be the main reason for blue duck decline. Other active threats include loss of habitat, poor riparian management and declining water quality. Evidence from around the country suggests that stoats kill a large number of juvenile ducks. In the Ruahine Forest Park 47 percent of fledged juveniles fell to predators. Stoat control on the Te Wai-iti Stream, on the edge of the Northern Te Urewera

Ecosystem Restoration Project, however, allowed successful breeding and survival of the young. The Central North Island Blue Duck Conservation Trust was established in August 2002, following negotiations with Genesis Power Ltd which was seeking to continue operating the Tongariro Power Development. The arrangement is for $1.5 million to be paid to the Trust over 10 years as part of a mitigation agreement signed by Genesis, the Department of Conservation and the Royal Forest and Bird Protection Society. The primary purpose of the new Trust is to mitigate any ongoing adverse environmental effects on blue duck resulting from the continued operation of the Tongariro Power Development. The planned mechanism is the creation of new self-sustaining populations of blue duck — not necessarily limited to the Tongariro region. Ancillary objectives include enhancing existing populations and aquatic ecosystems, and to inform and educate the public about the work of the Trust. The Trust believes it can improve the blue duck’s survival chances. It has already approved two projects in principle. It wants to establish a new blue duck colony on Mount Taranaki in the Egmont

National Park and, secondly, undertake a predator control study on the Manganui-a-te-ao River. New, viable, blue duck colonies provide additional security for the species, but their establishment in appropriate locations is not quite as easy as it sounds. Some years ago one bird, having been ‘translocated’, flew back to the Whakapapa River near Tongariro from Mount Taranaki thereby dispelling a widely held belief that blue ducks don’t fly very far. To succeed, there must be sufficient habitat to allow the colony to expand; a river system with a number of suitable fast flowing rivers may be necessary, rather than just one river. And the surrounding habitat needs to be relatively pest free. The lessons being learned from translocation are increasingly important. Many blue duck populations are small, fragmented and have extreme male-biased sex ratios. Recovery of these populations is likely to require augmentation with birds from more productive colonies elsewhere.