This species has been downlisted to Endangered because, although its range is extremely small, observations regarding its habitat use imply that it is not severely fragmented; however, the species has a very small population, which is suspected to be in slow decline owing to limited habitat degradation.
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.
Distribution and populationRukia ruki
14 cm. Medium-sized, all-dark, warbler-like bird. Uniform dark-brown with black bill, orange legs and conspicuous white "teardrop" below the eye. Voice Lively song, lilting warble very similar to song of Golden White-eye Cleptornis marchei of the Marianas. Hints Mostly found in remnant native forest, but ranges into disturbed areas nearby.
has a tiny occupied range (c.4 km2
) being recorded from four tiny islands in the Faichuk Group of the Chuuk (= Truk) lagoon, Federated States of Micronesia
(numbers in brackets after each island indicate estimated population in 1984): Tol South (382), Wonei (19), Pata (32) and Polle (93) (Engbring et al
. 1990). The population is still thought to number in the hundreds (G. Dutson in litt.
2003), and it is described as still common and easily found in native forest on the summit plateau of Tol South (D. Scott in litt
. 2011). Its population is thought to be in slow decline owing to continued habitat degradation.Population justification
The total population in 1984 was estimated at c.530 individuals (Engbring et al.
1990), perhaps including c.350 mature individuals. Trend justification
The species's population is assumed to be in slow decline owing to on-going low rates of habitat degradation. Ecology
The species has been recorded in old and secondary-growth stands of native forest, particularly the rich and well-developed forest above 400 m on Mt Winipot (Tol South), where fig trees Ficus
spp., native palms Clinostigma
and the endemic poison tree Semecarpus kraemeri
predominate, the latter possibly playing an important ecological role in the species's survival (Engbring et al
. 1990, C. Collins in litt
. 2007). It is also found in areas of native trees mixed with plantations (Engbring et al
. 1990, D. Scott in litt
. 2011), but densities are much lower (J. Lepson in litt
. 1999). It feeds by foraging for insects in the foliage (Engbring et al
. 1990). It is territorial; breeding has been observed in April, and the only recorded nest was in a S. kraemeri
tree, supporting the premise that a commensal and possibly mutual relationship exists between the two species (Pyle and Engbring 1988). Threats
Deforestation has occurred across much of Chuuk Archipelago, but forests on the plateau of Tol South, where this species lives, are apparently old-growth and relatively undisturbed (C. Collins in litt
. 2007). Access to the plateau is difficult (D. Scott in litt
. 2011) and hence the threat posed to the species is low. In addition, superstitious beliefs apparently inhibit islanders from trying to visit the plateau (C. Collins in litt
. 2011). Observations from Tol South suggest that little in the way of logging is now taking place there and that only subsistence-level timber extraction is occurring, owing to the topography of the island and areas of difficult terrain (C. Collins in litt
. 2011, D. Scott in litt
. 2011). The potential introduction of alien species to the islands is a concern, particularly brown tree snake Boiga irregularis
which has caused the extirpation and extinction of birds on Guam (to USA) (Engbring et al
. 1990). The species is potentially threatened in the future by the effects of projected climate change, such as shifts in habitat distribution and rising sea levels. Conservation Actions Underway
None is known, although a stamp featuring the species was issued by the Republic of Naurau in 2005. Conservation Actions Proposed
Conduct surveys to establish the current population size and trends. Protect suitable habitat, including native forest on Polle and above 250 m on Mt Winipot (Engbring et al
. 1990). Promote local awareness of this endemic species through an education programme (J. Lepson in litt
Engbring, J.; Ramsey, F. L.; Wildman, V. J. 1990. Micronesian forest bird surveys, the Federated States: Pohnpei, Kosrae, Chuuk, and Yap. U.S. Fish and Wildlife Service, Honolulu.
Pyle, P.; Engbring, J. 1988. First described nest and nest site activity of the Truk Greater White-eye Rukia ruki. Micronesica 21(1/2): 281-283.
Further web sources of information
Alliance for Zero Extinction (AZE) species/site profile. This species has been identified as an AZE trigger due to its IUCN Red List status and limited range.
Click here for more information about the Alliance for Zero Extinction (AZE)
Explore HBW Alive for further information on this species
Search for photos and videos, and hear sounds of this species from the Internet Bird Collection
Text account compilers
Bird, J., O'Brien, A., Shutes, S., Stattersfield, A., Symes, A. & Taylor, J.
Collins, C., Dutson, G., Lepson, J. & Scott, D.
IUCN Red List evaluators
Butchart, S., Symes, A.
BirdLife International (2016) Species factsheet: Rukia ruki. Downloaded from
http://www.birdlife.org on 31/05/2016.
Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from
http://www.birdlife.org on 31/05/2016.
This information is based upon, and updates, the information published in BirdLife International (2000)
Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004)
Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.
To provide new information to update this factsheet or to correct any errors, please email BirdLife
To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.
Additional resources for this species