Justification This species qualifies as Endangered because it has a very small population, which appears to be rapidly declining owing to loss of habitat within its small range. If this loss of habitat becomes chronic and causes the population to become severely frgamented then it may be uplisted to Critically Endangered.

Family/Sub-family Monarchidae

Species name author (Hombron & Jacquinot, 1841)

Taxonomic source(s) Sibley and Monroe (1990, 1993)

Identification 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.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

1,000-2,499

decreasing

80 km²

Yes

Range & 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 2,168¹. It subsequently appears to have become much rarer according to a recent population estimate in 2001³. 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 2005⁴. Though it was thought to have been extirpated from Weno, a major fire destroyed the patch of forest where it was uncommon in the 1970s², two males were seen in Sopo Forest in 2005⁴.

Ecology: It occurs at highest densities in small patches of upland native forest, but is also found in well-developed stands of mangrove, atoll strand and (rarely) plantations along scrubby slopes, often covered by hibiscus Hibiscus tiliaceus or along steep ridges or cliffs¹. It favours areas with a thick, leafy understorey where it is found in small family groups gleaning insects, lizards and other prey from the foliage¹. It appears to be strongly territorial, nesting in trees with dense foliage¹. Nesting has been recorded from April to July¹.

Threats 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 population¹ and consequent further loss of its habitat.

Conservation measures underway This species is the state bird of Chuuk and may obtain some conservation benefit from this recognition.

Conservation measures proposed Monitor the population¹. 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 mangrove¹.

References 1. Engbring et al. (1990). 2. H. D. Pratt in litt. (1994). 3. G. Dutson in litt. (2003). 4. C. Collins in litt. (2005).

Text account compilers Simon Mahood (BirdLife International), Andrew O'Brien (BirdLife International), Mark O'Brien (Royal Society for the Protection of Birds), Sue Shutes (BirdLife International), Alison Stattersfield (BirdLife International)

Contributors Chris Collins (Wildwings), Guy Dutson (Birds Australia), H. Douglas Pratt (North Carolina State Museum of Natural Sciences)

IUCN Red List evaluators Stuart Butchart (BirdLife International), Simon Mahood (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Metabolus rugensis. Downloaded from http://www.birdlife.org on 9/2/2010

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.

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