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Rukia longirostra 

Scope:Global
Status_ne_offStatus_dd_offStatus_lc_offStatus_nt_onStatus_vu_offStatus_en_offStatus_cr_offStatus_ew_offStatus_ex_off

Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Zosteropidae

Scientific Name: Rukia longirostra
Species Authority: (Takatsukasa & Yamashina, 1931)
Common Name(s):
English Long-billed White-eye, Large Ponhpei White-eye

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Raynor, B.
Facilitator/Compiler(s): Derhé, M., Mahood, S., O'Brien, A., Shutes, S.
Justification:
This species is listed as Near Threatened because it is restricted to one small island where it has undergone a slow decline over recent decades. Should the rate of decline significantly increase, the species would warrant uplisting to a higher threat category.

Previously published Red List assessments:
  • 2008 – Near Threatened (NT)
  • 2004 – Near Threatened (NT)
  • 2000 – Lower Risk/near threatened (LR/nt)
  • 1994 – Lower Risk/near threatened (LR/nt)
  • 1988 – Threatened (T)

Geographic Range [top]

Range Description:Rukia longirostra is endemic to the island of Pohnpei, Federated States of Micronesia, where, in 1983, it was common throughout the uplands but also present in the lowlands. The total population was estimated at 31,623 birds and its previously reported scarcity was thought to be the result of its inconspicuous nature and the inaccessibility of its montane habitat (Engbring and Pratt 1985, Engbring et al. 1990). However, in 1994, a repeat survey recorded a significant decrease in encounter rate in both the lowland and uplands, with nearly 90% of the sightings on c.10% of the land area (Buden 2000).

Countries occurrence:
Native:
Micronesia, Federated States of
Additional data:
Continuing decline in area of occupancy (AOO):Unknown
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:350
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:NoLower elevation limit (metres):600
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Engbring and Pratt (1985) estimated a population size of 31,623 individuals, which is rounded here to 31,600.

Trend Justification:  There are no recent data on population trends; however, surveys in 1994 found significantly fewer individuals than in 1983 (Buden 2000), thus a slow to moderate decline is suspected.
Current Population Trend:Decreasing
Additional data:
Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:No
Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No
No. of individuals in largest subpopulation:100

Habitat and Ecology [top]

Habitat and Ecology:It occurs in palm and broadleaf forest, rarely using plantations (Engbring et al. 1990). It feeds mostly on nectar, but also takes insects and sometimes fruit (Engbring et al. 1990). Its affiliation with the uplands may be the result of its nectarivorous feeding habits, which have allowed it to subsist on the nectar of the abundant native palm, and it may also be excluded from the lowlands by competition with other native passerines (Engbring et al. 1990).

Systems:Terrestrial
Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):4.4
Movement patterns:Not a Migrant

Threats [top]

Major Threat(s): Overall, there was a reduction of undisturbed upland forest on Pohnpei of over 60% from 1975 to 1995 (Buden 1996, 2000, B. Raynor in litt. 1995, 2012). The majority of the island's forests have been to various degrees converted or at least degraded to mixed forest (native species mixed with lowland secondary species), largely attributable to the cultivation of sakau (= kava) Piper methysticum, a major cash-crop (B. Raynor in litt. 2012). The fragmentation of such forest by sakau clearings also introduces and encourages the spread of invasive species in isolated areas throughout the forest. Although efforts over the past 20 years to reduce the amount of clear-cutting for sakau plantations have resulted in the slowing of native forest conversion rates, the trend remains negative (B. Raynor in litt. 2012). Long-standing tradition and custom surround the use of sakau, but this has given way to more widespread recreational use with the result that clear-cutting 1-2 ha plots for sakau has increased in recent years, reaching to the edge of cloud forest at c.600 m in some areas (Buden 2000). Since it is a single island endemic it is also at risk from to the accidental introduction of brown tree snake Boiga irregularis.

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
None is known.

Conservation Actions Proposed
Conduct surveys to monitor population trends. Protect the most important areas of forest for this species. Take measures to ensure B. irregularis never reaches Pohnpei.


Citation: BirdLife International. 2012. Rukia longirostra. The IUCN Red List of Threatened Species 2012: e.T22714271A39639471. . Downloaded on 26 July 2016.
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