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Chuuk Monarch Metabolus rugensis
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This species qualifies as Endangered because it has a very small population, which appears to be in rapid decline owing to the loss of habitat within its small range. If this loss of habitat becomes chronic and causes the population to become severely fragmented then it may be uplisted to Critically Endangered.

Taxonomic source(s)
Sibley, C. G.; Monroe, B. L. 1990. Distribution and taxonomy of birds of the world. Yale University Press, New Haven, USA.

20 cm. Large, striking flycatcher. Adult male nearly all white, with glossy blue-black face and throat and black primary tips. Some are tinged pale salmon or buff below. Females dark slate, most individuals blotched with rufous feathers retained from juvenile plumage. Juveniles bright rufous above, rufous-buff below with ill-defined, buff eyebrow. Similar spp. Juveniles similar to Caroline Reed-warbler Acrocephalus syrinx, but much brighter rufous above and with less defined supercilium. Voice No well-defined song. Calls include human-like whistles slurred up or down and plaintive, querulous u-waw, reflected in the local name. Hints Slow-moving and rather tame, but surprisingly difficult to see.

Distribution and population
Metabolus rugensis is widely but sparsely distributed on all, or nearly all, of the high lagoon islands, as well as some of the outer reef islets of Chuuk (= Truk), Federated States of Micronesia, with highest densities reported from Tol South. It has probably never been abundant in historic times. In 1984, numbers were estimated at 2,168 (Engbring et al. 1990). It subsequently appears to have become much rarer according to a population estimate in 2001 (G. Dutson in litt. 2003). On Tol South, no birds were found in a visit in 1991 and only 3-4 birds in 1993, although birds were seen again in 2005 (C. Collins in litt. 2005). It was thought to have been extirpated from Weno after a major fire destroyed the patch of forest where it was uncommon in the 1970s (H. D. Pratt in litt. 1994); however, two males were seen in Sopo Forest in 2005 (C. Collins in litt. 2005). The species now appears to be rare on Weno (C. Collins in litt. 2011), and according to local people it is becoming rarer on Tol South (D. Scott in litt. 2011). In addition, the species was not successfully located in December 2010 in an area on Dublon Island where it had been seen in December 2008 (D. Scott in litt. 2011).

Population justification
The population estimate of 1,000-2,499 individuals is derived from Engbring et al. (1990) and H. D. Pratt in litt. (1994). This equates to 667-1,666 mature individuals, rounded here to 600-1,700 mature individuals.

Trend justification
A population estimate in 2001 (G. Dutson in litt. 2003) suggested that the species had declined from the 1984 estimate (Engbring et al. 1990). The species is now thought to be rare on Weno (C. Collins in litt. 2011), and according to local people it is becoming rarer on Tol South (D. Scott in litt. 2011). Furthermore, it was not recorded in an area on Dublon Island in December 2010 where it had been seen in December 2008 (D. Scott in litt. 2011). On the basis of this information the population is suspected to be in rapid decline overall.

It occurs at highest densities in small patches of upland native forest, but is also found in well-developed stands of mangrove, thickets, atoll strand and (rarely) plantations along scrubby slopes, often covered by hibiscus Hibiscus tiliaceus or along steep ridges or cliffs (Engbring et al. 1990, D. Scott in litt. 2011). It favours areas with a thick, leafy understorey where it is found in small family groups gleaning insects, lizards and other prey from the foliage (Engbring et al. 1990). It appears to be strongly territorial, nesting in trees with dense foliage and nesting has been recorded from April to July (Engbring et al. 1990).

It is likely to have declined dramatically in the 1940s, owing to extensive agricultural development during the Japanese administration, and may still be gradually declining, most likely due to the rapidly expanding human population (Engbring et al. 1990) and consequent further loss of its habitat. Although it shows some flexibility in its habitat requirements, the species appears to prefer native forest, which on Tol South is now restricted to the summit plateau (D. Scott in litt. 2011). There are also second-hand reports that the species has been targeted with slingshots on Weno (C. Collins in litt. 2011).

Conservation Actions Underway
This species is the state bird of Chuuk and may obtain some conservation benefit from this recognition. Conservation Actions Proposed
Carry out comprehensive surveys to assess the current population size. Conduct regular surveys to monitor population trends (Engbring et al. 1990). Protect forest habitat, including the small patches of native forest remaining on the high islands, the atoll forest on the outer reef islands, and the more extensive stands of mangrove (Engbring et al. 1990). Assess the threat posed by direct persecution. Conduct awareness-raising activities to discourage persecution.

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.

Further web sources of information
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
Mahood, S., O'Brien, A., Shutes, S., Stattersfield, A., Taylor, J.

Collins, C., Dutson, G., Pratt, H., Scott, D.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2016) Species factsheet: Metabolus rugensis. Downloaded from on 24/10/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from on 24/10/2016.

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

ARKive species - Chuuk monarch (Metabolus rugensis) 0

Key facts
Current IUCN Red List category Endangered
Family Monarchidae (Monarchs)
Species name author (Hombron & Jacquinot, 1841)
Population size 600-1700 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 80 km2
Country endemic? Yes
Links to further information
- Additional Information on this species