|Blue duck at Staglands, Akatarawa Valley|
G.R. Gray, 1843
The blue duck (Hymenolaimus malacorhynchos) is a member of the duck, goose and swan family Anatidae endemic to New Zealand. It is the only member of the genus Hymenolaimus, placed in the shelduck subfamily Tadorninae after previously being considered part of the paraphyletic "perching duck" assemblage. The Māori name, sometimes used in English, is whio, which is an onomatopoetic rendition of the males' call.
The blue duck is depicted on the reverse side of the New Zealand $10 banknote.
The blue duck is a dark slate-grey with a chestnut-flecked breast and a paler bill and eye. The pinkish-white bill has fleshy flaps of skin hanging from the sides of its tip. The male's call is an aspirated whistle, and the female's is a rattling growl. The blue duck hatches with a green beak for just 8 hours after hatching; after which it then develops its final colour.
Ecology and behaviour
This species is an endemic resident breeder in New Zealand, nesting in hollow logs, small caves and other sheltered spots. It is a rare duck, holding territories on fast flowing mountain rivers. It is a powerful swimmer even in strong currents, but is reluctant to fly. It is difficult to find, but not particularly wary when located.
The blue duck is a very localised species now threatened by predation from introduced mammals such as stoats, competition for its invertebrate food with introduced trout, and damming of mountain rivers for hydroelectric schemes. It is listed as Nationally Endangered in the New Zealand Threat Classification System. In 2009 the New Zealand Department of Conservation started a ten-year recovery programme to protect the species at eight sites using predator control and then re-establish populations throughout their entire former range.
In 2011 the New Zealand Department of Conservation and Genesis Energy started the Whio Forever Project, a five-year management programme for Whio. It will enable the implementation of a national recovery plan that will double the number of fully operational secure blue duck breeding sites throughout New Zealand, and boost pest control efforts.
- BirdLife International (2013). "Hymenolaimus malacorhynchos". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- Madge, Steve; Burn, Hilary (1987). Wildfowl: an identification guide to the ducks, geese and swans of the world. London: Christopher Helm. ISBN 0-7470-2201-1.
- Glaser, Andrew; Andrew, Paul; Elliott, Graeme; Edge, Kerri-Anne (December 2010). Whio/blue duck (Hymenolaimus malacorhynchos) recovery plan 2009–2019. Threatened Species Recovery Plan 62. Wellington, N.Z.: Department of Conservation. ISBN 978-0-478-14841-1.
- Adams, J.; Cunningham, D.; Molloy, J.; Phillipson, S. (1997). "Blue duck (Whio) Hymenolaimus malacorhynchos recovery plan 1997–2007" (PDF). Wellington, New Zealand: Department of Conservation. Retrieved 7 November 2007.
- Whitehead, A.; Edge, K.; Smart, A.; Hill, G.; Willans, M. (2008). "Large scale predator control improves the productivity of a rare New Zealand riverine duck". Biological Conservation 141: 2784–2794. doi:10.1016/j.biocon.2008.08.013.
- Whitehead, A.; Elliott, G.; McIntosh, A. (2010). "Large-scale predator control increases population viability of a rare New Zealand riverine duck". Austral Ecology 35: 722–730. doi:10.1111/j.1442-9993.2009.02079.x.
|Wikimedia Commons has media related to Blue Duck.|
- ARKive: Images and movies of the Blue Duck (Hymenolaimus malacorhynchos)
- BirdLife Species Factsheet.
- Blue duck/Whio at the Department of Conservation
- TerraNature | New Zealand ecology - Blue duck (Whio)
- Blue Duck Project Charitable Trust
- Whio Forever Project
- Central North Island Blue Duck Trust