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Conservation Newsletter |
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This occasional newsletter provides conservation and environment news from the Chatham Islands.
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Wildlife
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The recovery of the Chatham Islands black robin from the brink of extinction
is an internationally renowned conservation success story.
In 1980 there were only five black robins in the world, with just a
single breeding pair left and confined to the tiny, almost inacessible
Little Mangere Island. The survival of the species hinged on that last
pair. A desperate and innovative management regime was quickly put into
action by the New Zealand Wildlife Service (now Dept of Conservation)
that resulted in robins being moved to Mangere island and then
Rangatira and resulted in a successful population turnaround. Today,
the population stands at around 200 adult birds.
Efforts to to establish black robins in the
predator-fenced Ellen Elizabeth Preece Conservation Covenant on Pitt
Island have thus far failed, with the most likely cause of translocation failure was mice competing
for the robin's insect and spider food. Mice are not present on the
mammal-free nature reserves offshore but are present on Pitt Island.
'Spike', the last robin to persist in the covenant, was last seen in
October 2007.
Because the black robin still has such a small population it is
classified as critically-endangered. The species is currently confined
to Rangatira and Mangere Nature Reserves to which public entry is not
permitted.
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Black robin
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| Despite their names, both the Chatham Island shag and the Pitt
Island shag are found around both islands. The Chatham Island shag is a
large black-and-white shag, closely related to the Stewart Island and
King shags of the New Zealand mainland. During the breeding season the
orange patches above and below the bill are at their most prominent and
contrast with the blue eye-ring.
The Pitt Island shag is more slender that the Chatham Island
shag. It is light grey underneath and has a lime-green face. The upper
side of the wings are spotted like those of the closey related mainland
species, the spotted shag.
Both species of shag are thought to
be in decline, but the nature and cause of decline are hard to
establish. Both species nest and roost on rocky headlands and islets
and are difficult to view without causing some disturbance. Please take
care approaching roosts and nesting sites, and back off if the birds
show signs of flight or nervousness. Good views can often be gained
from boats as the birds will often overfly boats near the shore. Both
species can often be seen from the Waitangi wharf.
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Chatham shag
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The Chatham Island mudfish looks so different to its relatives in
mainland New Zealand that its discovery in 1994 resulted in a case of
mistaken identity.
Charles Mitchell, who discovered it in Lake Tuku a Taupo while
undertaking an ecological assessment for the Chatham Island Electricity
Limited Trust, originally described it as belonging to the whitebait
group (Galaxiidae). But further investigation by Dr Bob McDowall in
2004 revealed it to be a mudfish, most closely related to the
Canterbury mudfish. This suggests they shared a common migratory
ancestor before traversing the 850km of ocean to the Chathams and
becoming landlocked and losing the migratory phase.
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Chatham Island mudfish
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Read more...
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In 1998 the Chatham Island oystercatcher was one of New Zealand's
most endangered birds, with a limited range and a population of only
142 birds. Management by restoring natural beach habitat (replacing
marram grass with native species), fencing out stock, and predator
control saw the population double by 2005. Oystercatchers can now be
seen on many of the beaches, particularly in the north.
While
the oystercatchers are now out of the critically endangered category,
they still need your help to survive. When visiting beaches be aware
that oystercatchers depend on the coast for their food and for a safe
place to rear their young. Nesting birds are easily disturbed and when
approached they will often walk or run away from the nest. They may
seem agitated or will run and hide behind objects, trying to draw
you away from the nest. Those with chicks are often noisy and may swoop
to chase you away.
- If oystercatchers appear to be disturbed by your presence at a site, move further along the beach.
- Keep dogs under control
- Walk or drive under the high tide mark to avoid crushing eggs or chicks
New DOC brochure here (pdf - 576kb)
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Chatham Island oystercatcher
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The Chatham Island snipe is a small, squat, long-billed bird with
dappled brown plumage. They use their long bill to probe for
invertebrates in the soil and are active foragers day and night. Snipe
are resricted to predator-free islands and the Rangatira Island Nature
Reserve is the stronghold of the population.
In May 2008, 20 snipe were transferred to a predator-fenced area in the Ellen
Elizabeth Preece Conservation Covenant on Pitt Island. Guided access to the covenant can be arranged by contacting Flowerpot Adventures.
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Chatham Island snipe
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Thought extinct until its rediscovery by David Crockett in 1979, the Chatham Island Taiko or Magenta petrel are extremely rare and only
occur in the Tuku Nature Reserve on Chatham Island.
Cats, rats, and pigs have contributed to their decline and the population now stands at around 15 breeding pairs. to which access is
restricted. Burrow management and predator control has improved the survival of taiko chicks and efforts are still given to searching the thick forest for more taiko burrows.
Given the very small population and critically endangered
status of the species it is not possible for the public to see them - access to the Tuku Nature Reserve is by special permit only.
For more information contact the Department of Conservation or visit www.taiko.org.nz. |
Chatham Island taiko
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The Chatham Island tomtit is very similar to its mainland counterpart although, like many island birds, slightly larger.
Extinct on Chatham Island since the 1970's, the CI tomtit now numbers around 1,000 birds and is currently restricted to the rat-free islands of Rangatita, Mangere and Pitt, although the Taiko Trust is working on a proposal to translocate tomtits to a predator-controlled site in the Awatotara valley in the South Chathams.
The Ellen Ezlbabeth Preece Conservation Covenant (Caravan Bush) on Pitt Island is the best place for visitors to view Chatham Island tomtits.
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CI tomtit
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The Chatham Island tui is a subspecies of the tui found on mainland New Zealand. It both larger and with longer throat tufts than it's mainland counterpart and the song is also significantly different.
Formerly widespread on the Chatham Islands, tui numbers on Chatham Island declined throughout the 20th century and by 1990 were confined to Pitt and Rangatira Islands where they are relatively abundant.
In March 2009 the Taiko Trust translocated 14 juvenile to the Awatotara valley in South Chathams. All tui survived their first winter and there are indications of breeding activity.
Tui feed on nectar, fruit and insects and are important for the pollination and seed dispersal of native forest plants. Tui is the only remaining honey eater on the Chatham Islands, following the extinction of the Chatham Island bellbird in the early 1900's.
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Chatham Island tui
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The Chatham Island pigeon or parea (Hemiphaga chathamensis) is one
of two species of native pigeon in New Zealand.
Twenty percent heavier than the NZ pigeon, its dorsal plumage and upper
breast is more purple and pearl-grey than its mainland counterpart, but it has
the same white lower breast, shoulder straps and belly. The bill is red with and
orange tip.
Parea fly with noisy wingbeats, and during the breeding season they perform
conspicious display dives - flapping upwards from their perch and then stalling
and diving sharply down.
Parea feed on a wide range of leaves and fruit with hoho (Pseudopanax
chathamicus) being particularly important. Parea spend considerable time
on the ground grazing and often nest close to the ground, making them easy targets for feral cats.
While relatively rare and confined to the south-west of Chatham
Island, numbers have grown in the past few years and it can often be
seen from the roadside in the vicinity of Awatotara stream. Sightings
of parea can be reported online here.
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Parea |
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Buff weka were introduced to the Chatham Islands from Canterbury in
1905. They have prospered in the absence of mustelid predators
(ferrets, stoats and weasels), which is fortunate as the subspecies has
been extinct in its original eastern South Island range since the
1930s. While weka are protected in the rest of New Zealand they can be
legally harvested in the Chathams, and weka-hunting during the
non-breeding season is a popular activity. The importance of weka to
the Chathams community is manifested in the islanders refering to
themselves as "Weka" whereas mainlanders are "Kiwis".
Weka can be seen throughout the main island and on Pitt Island, where they were introduced in the 1970s. |
Buff weka
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