Rarotonga flycatcher (Pomarea dimidiata)

Also known as: Cook Islands flycatcher, Kakerori, Rarotonga monarch
KingdomAnimalia
PhylumChordata
ClassAves
OrderPasseriformes
FamilyMuscicapidae
GenusPomarea (1)
SizeLength: 14 cm (2)
Weight22 g (3)

The Rarotonga flycatcher is classified as Vulnerable (VU) on the IUCN Red List (1).

In 1989, this small flycatcher was one of the ten rarest birds in the world, teetering on the brink of extinction with a declining population of just 29 birds. Thanks to an intensive conservation programme, however, the bird has made a spectacular recovery (3). Both males and females progress through the same characteristic sequence of plumage colouration as they age, which allows different age groups to be identified easily (3). Year-old birds are bright orange, with a yellow base to the bill; two year-olds retain the orange colouration, but the base of the bill becomes dark blue; three year-olds have a variable mixed grey and orange plumage and a black bill; all birds over four years of age are entirely grey and retain the black bill (2) (3). The Maori name of the bird, kakerori, is onomatopoeic of the loud territorial call given by males (2).

Endemic to Rarotonga, the largest of the Cook Islands, where it is found only in the Totokoitu, Turoa and western Avana Valleys (2). Until the middle of the 19th century, the kakerori was fairly common, but by the early 1900s it was believed to be extinct (2). Numbers were found to be worryingly low in the 1980s, and by 1989 just 29 individual kakerori remained. An intensive programme of conservation has rescued this species from the brink of extinction, and in August 2001 10 birds were relocated to the Island of Atiu, where successful breeding has since occurred (3).

Found in forested steep-sided wet valleys that are sheltered from prevailing south-east trade winds (2).

The kakerori is a highly inquisitive and very territorial bird (3). Most one and two year old birds tend to form flocks away from territories, although some join their parents and help them to defend their territory and raise further young (3). Adult pairs remain in their territories throughout the year. They breed from October to February, with most eggs being laid in October and early November (3). The bulky nests are typically built of moss in a forked tree branch overhanging a stream (3) (4). One to two eggs are laid per clutch, and if a nest fails, pairs are able to produce a second clutch (3). Although kakerori are diminutive birds, they defend their nests fiercely; if an introduced ship rat (Rattus rattus) threatens the nest, the adults will stay and fight to the death (4).

The main factor thought to be responsible for the dramatic decline of the kakerori is predation by the introduced ship rat (Rattus rattus), which continues to be the biggest problem facing the species. Cats (Felis cattus) are also thought to predate juveniles and adult birds (3). Due to the very small range of this species, it is still vulnerable to chance events, such as cyclones or the introduction of a new predator or disease (2).

The kakerori has been rescued from the brink of extinction by a devoted conservation initiative, with the close involvement of local landowners. The Takitumu Conservation Area was set up in 1996, building on the work of the Kakerori recovery Programme, initiated in 1987. The valleys that support the kakerori are owned by three traditional landowning clans, the Kainuku, Karika and Manavaroa families, who joined forces to save the unique and highly endangered kakerori. The three families took over management of the project and formed a co-ordinating committee in 1996 (4) and are now developing an economically sustainable ecotourism project (2). Intensive rat control and nest protection began in the area in 1989, and an annual census of the population has since been taken every spring. The population increased every year, reaching 100 individuals in 1995, 200 by 2000 and 248 by 2001. In 2000 BirdLife International downgraded the status of the species from Critically Endangered to Endangered, then down to Vulnerable in 2012, a fitting reward for the efforts of this intensive conservation programme. Since 2002 the focus of the project has shifted from recovery to sustainable management of the population. The very high vulnerability of the single Rarotonga population to chance events, such as cyclones, led to the establishment of a second population on the rat-free island of Atiu in 2002. Early indications that this population is breeding successfully show that the kakerori’s eggs are now no longer in one basket.

BirdLife International 2003 BirdLife’s online World Bird Database: the site for bird conservation. Version 2.0. Cambridge UK: BirdLife International:
http://www.birdlife.org

Warrior bird, warrior people- three clans cooperate and save a species in the Cook Islands. United Nations Development Programme:
http://www.undp.org.ws/Portals/12/documents/samoa/publications/Stories%20Cook%20Islands%20.pdf

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
arkive@wildscreen.org.uk

  1. IUCN Red List (August, 2012)
    http://www.iucnredlist.org/
  2. BirdLife International 2003 BirdLife’s online World Bird Database: the site for bird conservation. Version 2.0. Cambridge UK: BirdLife International (March, 2004)
    http://www.birdlife.org/
  3. Saul, E.K. and Robertson, H.A. (2004) Conservation of the kakerori (Pomarea dimidiata) on the Cook Islands in 2002/03. DOC Science Internal Series 167. Department of Conservation, Wellington, New Zealand.
  4. Warrior bird, warrior people- three clans cooperate and save a species in the Cook Islands. United Nations Development Programme (September, 2010)
    http://www.undp.org.ws/Portals/12/documents/samoa/publications/Stories%20Cook%20Islands%20.pdf