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Declines & Status
Historical distribution and declines
A map of the South Island illustrating the decline in distribution of mohua
between about 1850 (shown in grey) compared to populations in 1990 (shown in black).
Mohua populations are even more restricted in range in 2012. (Map source: Mohua Recovery Plan 2002 – 2012, Department of Conservation)
Declines
Mohua began to decline noticeably around the 1890s but their populations have contracted gradually over many years. Between 1900 and 1930 mohua disappeared from many localities on the West Coast, Stewart Island, Nelson and Marlborough. Mohua were last recorded on Banks Peninsula around 1900 and have been extinct on Stewart Island since 1930. During the 1950s large flocks of mohua disappeared from the Mariua and Grey valleys of North Westland.
Well-known ornithologist and aristocrat, Perrine Moncrieff, used to visit Lake Rotoroa in the Nelson Lakes National Park, where in the 1930s she described the yellowhead as second only to the bellbird in abundance. At the time there had been some contraction of the yellowhead range but there was little reason to fear it would suffer from the effects of colonisation as it had clearly weathered the worst of this storm and was still thriving. However, by the 1960s the mohua had disappeared completely from Nelson Lakes National Park, and this trend was repeated elsewhere around the South Island at a rate that lead biologists to fear for the mohua’s long-term survival. During the 1980s it was recognised that mohua had disappeared from 75% of their former range and that declines were continuing.
Threatened species status
The World’s Threat Classification System
In 2012 mohua were ranked on the IUCN’s Red List of Threatened Species as Endangered, only three rankings away from becoming EXTINCT!
The IUCN’s threatened species rankings of mohua have moved up the ladder towards extinction since their first ranking in 1988. Efforts by conservationists may have so far saved the species from extinction but further work is required as mohua continue to decline. Over the past two decades the IUCN ranking has been elevated from Near Threatened in 1988, to Vulnerable in 1994 and to their current status of Endangered which they received in 2005 (and was updated in 2008 and 2012).
Web: View further information on the IUCN’s Red List of Threatened Species website
www.iucnredlist.org including the history of the ranking since 1988.
New Zealand’s own Threat Classification System
The New Zealand Government’s Department of Conservation uses the New Zealand Threat Classification System to rank the threatened status of native species. In 2012 mohua were ranked on this system as Nationally Vulnerable, again just three rankings away from extinction!
The New Zealand Threat Classification System categories:
Not Threatened At Risk Threatened Extinct
Naturally Uncommon Relict Recovering Declining Naturally Vulnerable Nationally Endangered Nationally Critical
Web: To learn more about the New Zealand Threat Classification System visit
www.doc.govt.nz/
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