|Scientific Name:||Rukia ruki|
|Species Authority:||(Hartert, 1897)|
|Red List Category & Criteria:||Endangered C2a(ii) ver 3.1|
|Reviewer/s:||Butchart, S. & Symes, A.|
|Contributor/s:||Collins, C., Dutson, G., Lepson, J. & Scott, D.|
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.
Rukia ruki 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.
Native:Micronesia, Federated States of
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The total population in 1984 was estimated at c.530 individuals (Engbring et al. 1990), perhaps including c.350 mature individuals.|
|Habitat and 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 spp., Parinarium, Randia 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).|
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. 1999).
|Citation:||BirdLife International 2012. Rukia ruki. In: IUCN 2012. IUCN Red List of Threatened Species. Version 2012.2. <www.iucnredlist.org>. Downloaded on 21 May 2013.|
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