Blue duck Hymenolaimus malacorhynchos

Description

• Grey-blue duck with pink bill.
• Males give characteristic, hoarse whistle “whio”, while females give a rattling “crack” call.
• Juveniles have a grey bill and lack chest plumage colouration.

Interesting Facts

• Formerly widespread on fast-flowing, hill-country streams mostly within indigenous forest.
• Range now much reduced, centred on Volcanic Plateau and Te Urewera in North Island and western side of Southern Alps.
• Possess a fleshy lobe to undersurface of bill believed to assist with gleaning invertebrates from rocks and aquatic debris.
• Pairs are territorial all year.
• Nest under cover on stream banks.

Association with Plantations

• Can be found in high quality and remote streams within plantation forest estates.
• Most associations with plantations are in the Central North Island and West Coast areas.

Threats

• Predation of eggs, young and adults by stoats and other predators.
• Loss of native forest and shrubland habitat along streams through development.
• Habitat flooding locally through hydro-electricity development.
• Shooting, particularly in the past.
• Trout may compete for food in some areas.

Management Options and Methods

• Protection of wide riparian zones of indigenous species along streams likely to be used by whio.
• Consider implementing predator control if pairs of whio are present and/or other groups (e.g. community/DOC) are implementing predator control in adjoining areas. Target predators are primarily mustelids and cats (refer kiwi).
• Comply with best forest operational management practices to avoid damage to riparian areas and saltation of streams.
• Raise awareness of staff and contractors of the presence of whio and the need to protect them.

Monitoring Options

• Survey for presence of whio looking for birds, their sign (white faeces on rocks in streams) and listening for calls.
• Contact local DOC staff for contributing to any existing monitoring programmes locally.
• Maintain records of sightings, including broods.
• Report findings to DOC.

Further Information and Support

• Blue duck recovery plan. Threatened Species Recovery Plan 22. Department of Conservation.
• Heather and Robertson 2000. The Field Guide to the Birds of New Zealand.
• Predator control and monitoring – Department of Conservation.
• Whio: Saving New Zealand’s Blue Duck by David Young (2006, Craig Potton Publishing NZ).
• Department of Conservation website.