Download Kakerori Recovery Plan - Invasive Species Specialist Group

12/6/2007
Kakerori Recovery Plan: A Conservation / InvasiveSpecies Management Case Study
The protection of an endemic Rarotongan bird, the kakerori, by
controlling rats in the Takitumu Conservation Area, Rarotonga
Written by Sarah Hoffmann (IUCN SSC Invasive Species Specialist
Group)
The Threat That Invasive Species Pose to Endemic PacificIsland Bird Species
When humans arrived in the Isles of Pacifica about 3500 years ago
they brought with them mammals such as ship rats (Rattus rattus)
(Irwin 1992, in Robertson et al. 1994), which, due to their predatory
instincts, decimated many of the local bird species in New Zealand,
Hawaii and the eastern Polynesian archipelagoes. It is a common fact
that rats commonly take eggs from birds’ nests and cats (Felis
domesticus) commonly prey on adult birds, fledglings and nestlings.
An Introduction to the Kakerori
The genus Pomarea consists of five species of flycatchers, all of which
are small insectivorous forest birds found on various islands in eastern
Polynesia, especially on high volcanic islands (Robertson et al. 1994).
All five species are considered endangered, rare or vulnerable
(International Union for the Conservation of Nature 1990, in Robertson
et al. 1994). This makes them a suitable target for protection and
concerted conservation efforts. This would ideally include the
management of invasive species such as the ship rat if appropriate.
The endangered kakerori (Pomarea dimidiate), which is also known as
the Rarotonga flycatcher, the Rarotongan monarch or the Pomarea
flycatcher, is in urgent need of both study and conservation. The
kakerori is endemic to a few small valleys in the Takitumu
Conservation Area, which is located in the southeastern part of
Rarotonga, Cook Islands (Robertson et al. 1994). Once widespread,
this remnant population is thought to have declined due to rat
predation (Robertson et al. 1994). The small population (about 300
birds in 2005, Robertson and Saul 2007) and isolation of the kakerori
mean there is a heightened need prioritise it for conservation. As
1
unique component of the Cook Island’s native avi-fauna, the kakerori
is a valuable genetic and eco-tourism resource well-worth preserving.
A Short History of Kakerori Conservation
Since 1988, the Cook Islands Environment Service has developed a
kakerori recovery plan on Rarotonga (and neighbouring Atiu where the
bird has been introduced) with assistance of conservation volunteers
and New Zealand scientists. Robertson and colleagues developed the
following objectives for the kakerori recovery plan in 1994:







to undertake annual monitoring of the kakerori population
to develop an effective predator control program
to protect kakerori nests and study supplementary feeding
to transfer kakerori individuals to another predator-free island
to study the habitat of the kakerori
to increase public awareness of kakerori conservation, and
to develop appropriate international trading policies regarding
the trade in endangered species.
The only valleys where the kakerori inhabits are now established as
the 155 ha “Takitumu Conservation Area” and are now managed by
the three landowning families (the Kainuku, Karika and Manavaroa
families). Since 1996 these families have developed an ecologically
sustainable and commercially viable eco-tourism programme (BirdLife
International 2007). This was initiated by the South Pacific Biodiversity
Conservation Programme and the following broader initiatives were
added to the previous conservation-focused aims (Robertson and Saul
2006):



to protect and enhance the TCA’s biodiversity values
to generate income for the landowners, and
to develop a sustainable eco-tourism venture.
Implementation of the Kakerori Recovery Plan
To fulfill the aim of developing an effective predator programmes
conservationists started a pilot rat-poisoning regime in 1989 and as
kakerori breeding success appeared to increase in response to this
treatment, rat-poisoning became an annual event from 1992 onwards
(Robertson et al. 1998, in Robertson and Saul 2006).
Kakerori have also been translocated to the neighbouring islet of Aitu
where they have been reported to be breeding successfully (BirdLife
2
International 2003a 2003b). The translocation was supported by
SPREP and the New Zealand Overseas Development Assistance Pacific
Initiative for the Environment (BirdLife International 2003a).
Results of Invasive Species Management
The kakerori was one of the ten rarest bird species in the world in
1989, with a declining population of less than 30 birds. As a result of
conservation and invasive-species management the kakerori
population reached about 300 birds in 2005 (Robertson and Saul
2006). Conservation efforts have contributed to the kakerori
population increasing and have allowed the species to be moved out of
the critically endangered category and into the endangered category
on the IUCN Red List (BirdLife International 2003).
Future Aims and Developments in the Kakerori Recovery Plan
The small isolated kakerori population is recovering. However,
conservationists consider on-going monitoring and preservation to be
necessary for increasing the likelihood of the species surviving in the
long-term. Occupying less than 200 ha, the kakerori population is at
risk of decline or extinction, for example, from a major catastrophic
event such as one of the tropical cyclones which frequently plague the
Pacific region (Robertson and Saul 2006). Follow-up management
including establishing populations of kakerori on other islands is taking
shape and has included the introduction of kakerori to Atiu between
2001-2003 (Robertson and Saul 2006).
The future direction of the kakerori conservation programme appears
to be focused on the following points (Robertson and Saul 2006):




maintaining rat-poisoning regimes in the Turoa, Totokoitu and
Lower Avana Valleys on Rarotonga
comparing the breeding success of kakerori breeding pairs in
territories with and without rat-poisoning
monitoring the survival and breeding of kakerori on Atiu, and
reporting results back to the Cook Islands community.
A Note on Eco-tourism on Rarotonga
The conservation managers of the Takitumu Conservation Area
initiated eco-tourism objectives as part of the conservation
management strategy of the area. The main activities in the Takitumu
Conservation Area are nature walking and bird-watching. Nature tours
3
began in 1998 and these have generated income which is helping both
the community and kakerori conservation. A souvenir shop is also
generating some income, however, it is not yet self-sufficient (Invasive
Species Specialist Group 2003).
References
BirdLife International. 2003a. First Kakerori fledglings on Aitu.
(Downloaded on 06.12.07, from:
http://www.birdlife.org/news/news/2003/04/kakerori.html)
BirdLife International. 2003b. New Kakerori population founded.
(Downloaded on 06.12.07, from:
http://www.birdlife.org/news/news/2001/08/486.html)
BirdLife International. 2007. Species factsheet: Pomarea dimidiata.
(Downloaded on 08.11.07, from: http://www.birdlife.org on
8/11/2007). (Information based on text in BirdLife International. 2000.
Threatened birds of the world. Barcelona and Cambridge, UK: Lynx
Edicions and BirdLife International, and BirdLife International. 2004.
Threatened birds of the world 2004 CD-ROM.)
Invasive Species Specialist Group. 2003. Takitimu Conservation Area
(Cook Islands) - Landowning clans in charge of the Kakerori Recovery
Programmes. In: Aliens 17. Invasive Species Specialist Group of the
IUCN Species Survival Commission.
Robertson, H.A. Hay, J.R., Saul, E.K and McCormack, G.V. 1994.
Recovery of the Kakerori: An Endangered Forest Bird of the Cook
Islands, Conservation Biology 8 (4): 1078-1086.
Robertson, H.A and Saul, E.K. 2006. Conservation of kakerori
(Pomarea dimidiata) in the Cook Islands in 2005/06. DOC Research &
Development Series 285. Science & Technical Publishing. Department
of Conservation: Wellington.
Robertson, H.A. and Saul, E.K. 2007. Conservation of kakerori
(Pomarea dimidiata) in the Cook Islands in 2005/06, in DOC Research
& Development Series 285. New Zealand Department of Conservation:
Wellington.
4