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Nine native bird species edge closer to extinction - global assessment1 June 2005 - Wellington Contact: Kevin Hackwell, ph
04 801 2215 (w) 04 389 4815 (h) 021 227 8420 Two
New Zealand native bird species - red-fronted parakeet (kakariki) and rock wren
- have been added to the list of globally threatened birds following an international
reassessment of the world's threatened bird species released today. A further
seven native bird species have had their global threat status upgraded to a higher
threat category. Notes BirdLife International
is a global alliance of non-government conservation organisations working in more
than 100 countries who, together, are the leading authority on the status of birds,
their habitats and the issues and problems affecting bird life. Forest and Bird
is the New Zealand Partner of BirdLife International. In the latest 2005 assessment 1,212 bird species are considered
threatened with extinction (i.e. in the categories of Critically Endangered, Endangered
and Vulnerable). This represents 12.4% of the total of 9,775 extant bird species
in the world. An additional 788 species are considered Near Threatened, giving
a total of exactly 2,000 species that are urgent priorities for conservation action.
Five species are known to have become
extinct in New Zealand since 1900: Background to individual bird species Orange-fronted Parakeet (Cyanoramphus malherbi) Upgraded from Endangered to Critically Endangered:
Orange-fronted parakeet was listed as Endangered previously because of an extremely
small and declining population (estimated to number 200-500 individuals) and range
at just two locations. However, in 1999-2000 numbers crashed from several hundred
to low tens as a result of rat and stoat plagues in two successive summers. The
population has remained very low since, hence its new Critically Endangered listsing.
The Government is intensively managing the last remaining populations of orange-fronted
parakeets (see Forest and Bird's May 2005 magazine for details). Upgraded from Endangered to Critically
Endangered: Chatham Island shag was listed as Endangered previously because it
lives in an extremely small area on three islands. However, surveys in 1997 found
840 pairs, but in 2003 only 270 pairs were counted. The cause of decline is unclear
. The breeding area totals less than one hectare, as the species breeds on just
a few ledges. This now Critically Endangered species could be extinct by 2020. Upgraded from Vulnerable to Endangered: Kaka
was listed as Vulnerable previously because it had a small population which was
estimated to be declining at a rate of over 10% in three generations (around 45
years). However, new information indicates that this species has almost disappeared
from the mainland except for a few intensely managed sites, from having been common
and widespread a century ago. Stoat predation is the main cause of mortality and
particularly affects nesting females, so quite large numbers of males can remain
highly visible for a long time after most females have disappeared. Kaka appear
to have declined by over 50% over the last 45 years, and are now considered to
be Endangered. Upgraded
from Vulnerable to Endangered: Yellowhead/mohua were listed as Vulnerable previously
because they have a small range and population which was severely fragmented and
declining. However, new information indicates that this species has undergone
a severe recent decline and are now classed as Endangered. The population is estimated
to have declined by more than 50% in ten years. From 1982-1993, out of 14 monitored
populations, one became extinct, five declined significantly (three to the verge
of extinction), one population increased, and seven didn't change significantly,
Since then, this species was also very seriously affected by the 1999-2000 rat
and stoat plagues, with two populations undergoing local extinction, and three
more having significant population crashes. Some populations have now been established
on offshore islands. (See Forest and Bird's May 2005 magazine for more information.) Upgraded from Vulnerable to
Endangered: New Zealand Dotterel has a small and fragmented population and a small
and severely fragmented range. It faces threats from coastal development, predation
from cats and stoats and disturbance by people, their vehicles and their pets.
The population is maintained through intensive management. Increasing concern
over the dotterel's dependence on intensive management has caused the upgrade
in status from Vulnerable to Endangered. Black-billed Gull (Larus bulleri) Upgraded from Vulnerable to Endangered: Black-billed Gull was listed as Vulnerable previously because it was estimated to be declining by more than 30% over three generations owing to a variety of threats causing breeding failures at colonies. However, new evidence suggests the declines may be even higher. The main threats are predation by pests, weed spread, changes to habitat through hydroelectric development and irrigation and other forms of human disturbance. This species is in steep decline on its main breeding grounds on South
Island braided riverbeds. At one minor colony in the Hunter Valley, Otago, which
was recently resurveyed, numbers had dropped from 581 in 1969 to just 12. The
same trend was seen in the nearby Makarora catchment. The largest population is
in Southland, where the Oreti River population declined from 84,900 breeding birds
counted in 1974 to 15,308 in 1997. Six rivers in the upper Waitaki lost all their
breeding colonies. Overall declines are now estimated to exceed 50% over three
generations and this has led to an upgrade in status to Endangered. (See Forest
and Bird's May 2005 magazine for more details.) Upgraded from Vulnerable to Endangered: Pitt Island Shag
was classified as vulnerable because it lives on a small area and has a small
population (estimated to be 729 breeding pairs in 1997). This makes it vulnerable
to the effects of human activities and random events. New information suggests
that its population has declined 25% over six years to 2003 and so it has been
upgraded to Endangered. Pitt Island Shag could be extinct by 2020. Upgraded from Least Concern
to Vulnerable: Red-fronted parakeet was listed as Least Concern previously. The
species was historically extremely abundant on mainland New Zealand, and also
occurred on various offshore island groups. It is now effectively extinct on the
mainland: recent sightings are now believed to be cage escapes/releases or vagrants
from offshore island populations. It is still found on the Kermadec islands, Three
Kings, some Hauraki Gulf islands, Kapiti Island, Stewart Island and surrounding
islands, Chatham Islands, Snares, and as a hybrid swarm (with Yellow-crowned parakeet
C. auriceps) on the Auckland Islands. Declines are likely to be taking place on
Stewart Island (by inference from measured declines of other species owing to
rat and cat predation). The population has now become fragmented and is considered
Vulnerable. Upgraded from
Near Threatened to Vulnerable: Rock Wren was listed as Near Threatened previously.
However, a recent analysis of sightings indicates that about one fifth of known
localities have had no sightings in the past 20 years. Therefore it is now classed
as Vulnerable. The only study on nesting in this species showed significant levels
of egg and chick loss to mice and stoats. The closely related Bush Wren became
Extinct in the second half of the 20th Century. Hawkins' Rail was known from the Chatham Islands. It was not
classified as Extinct because its extinction was thought to have occurred before
the cut-off date of 1500. However, recent evidence including a letter from Sigvard
Jacob Dannefarerd to Lord Lionel Walter Rothschild in 1895 describing the species'
appearance, behaviour and Moriori hunting method suggests that this species survived
into at least the 1800s. It has therefore been classified as recently extinct. | ![]() |