Justification of Red List Category
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.
Engbring and Pratt (1985) estimated a population size of 31,623 individuals, which is rounded here to 31,600.
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.
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).
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).
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 Underway
None is known.
Text account compilers
Derhé, M., Mahood, S., O'Brien, A., Shutes, S.
BirdLife International (2019) Species factsheet: Rukia longirostra. Downloaded from http://www.birdlife.org on 23/09/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/09/2019.