Rarotonga monarch
| Rarotonga monarch | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Passeriformes |
| Family: | Monarchidae |
| Genus: | Pomarea |
| Species: | P. dimidiata |
| Binomial name | |
| Pomarea dimidiata (Hartlaub & Finsch, 1871) | |
The Rarotonga monarch (Pomarea dimidiata), Cook Islands Māori: Kākerōri, also known as the Rarotonga flycatcher,[2] is a species of bird in the monarch flycatcher family Monarchidae. It is endemic to the Cook Islands.
It is a most unusual bird in a number of ways, being the only bird known to undergo sequential changes in plumage as it grows [3] from orange to orange-grey to pure grey when maturity is reached after four years. Owing to its tropical oceanic island location, the kakerori is exceptionally long-lived for a bird with a mass of 22 grams (0.8 oz),[3] having an adult survival of between 85 and 89 percent, a life expectancy of seven to nine years, and a maximum lifespan from a single banding scheme started in the middle 1980s of around 24 years. These figures are comparable to large Australian passerines like the superb lyrebird or satin bowerbird[4] and more than ten times the life expectancies of similar sized Holarctic songbirds. Such extraordinary longevity may explain the evolution of helpers at the nest in a family where this feature is otherwise completely absent:[5] males can breed at one year, but do not do so in practice until they are four.[6]
Since the introduction of the black rat and feral cat adult mortality has more than doubled, a change sufficient to reduce what was previously a highly numerous bird[6] to one of the most endangered birds in the world by the middle 1980s, when the kakerori was listed as one of the highest conservation priorities among all Pacific Island birds.[7] The removal of rats has made breeding more successful: around two thirds of pairs assisted by a few helpers can now rear both of the normal clutch of two eggs, whereas in the 1980s breeding attempts had a success rate as low as eleven percent.[6] Despite the growth in population, it is still known that a major tropical cyclone could destroy this growth with extreme swiftness, so that conservation work is still very important.
References
- ↑ BirdLife International (2012). "Pomarea dimidiata". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- ↑ "Rarotonga Flycatcher". Cook Islands Biodiversity & Natural Heritage. Retrieved 7 March 2013.
- 1 2 “Conservation of kakerori (Pomarea dimidiata) in the Cook Islands in 2004-05”
- ↑ See Australian Bird and Bat Banding Scheme
- ↑ Distribution of known and inferred modes of parental care in families and subfamilies of birds
- 1 2 3 “Breeding biology of the kakerori (Pomarea dimidiata) on Rarotonga, Cook Islands”
- ↑ Review of avifauna conservation needs in Polynesia