email a friend
printable version
VU
Fly River Grassbird Megalurus albolimbatus

Justification
This species is classified as Vulnerable, as its small population is divided into a handful of subpopulations within a small range and, at least locally, is in decline. However, there is little information on this species and improved knowledge of distribution and abundance could result in downlisting to Near Threatened.

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

Identification
15 cm. Medium-sized warbler. Generally streaky-brown with plain, bright tawny-orange crown and rump, white supercilium, clear whitish underparts, tertials boldly edged white and moderately long, slightly rounded, tail. Similar spp. Tawny Grassbird M. timoriensis has longer, spiky tail and duller underparts and supercilium. Beware also female White-shouldered Fairy-wren Malurus alboscapularis which is darker, lacks the rufous and has different habits. Voice Number of harsh calls, notably repeated quiet whistled zeee and sweet chirping song. Hints Most sites are only accessible in the dry season and even then only by boat.

Distribution and population
Megalurus albolimbatus is known from a few localities in the Trans-Fly region of New Guinea (Papua, formerly Irian Jaya, Indonesia and Papua New Guinea), including Wasur National Park, small areas along the Bensbach River and a handful of sites on the middle Fly River (Coates 1990, Gregory and Jaensch 1995, N. Stronach in litt. 1996). It is thought to have a patchy, perhaps relict, distribution, but may prove to be more widespread in the largely unsurveyed Trans-Fly or on Pulau Dolak (= Frederick Henderik Island) (P. Gregory in litt. 1996, K. D. Bishop in litt. 1999). It is reported to be locally numerous in tiny scattered areas (Coates 1990, N. Stronach in litt. 1996) but most recent records in Papua New Guinea have been of very few individuals (Finch 1980, Eastwood and Gregory 1995, Gregory and Jaensch 1995).

Population justification
The population is estimated to number 2,500-9,999 individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied. This estimate is equivalent to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals.

Trend justification
A moderate and on-going population decline is suspected based on rates of habitat change through agricultural development, and the negative impacts of invasive species.

Ecology
It is apparently highly specialised in its breeding habitat requirements. On the Fly River, it inhabits a mixture of reeds, floating grass and lotus lilies growing on deep waterways and lakes (Rand 1938, Gregory and Jaensch 1995). On the Bensbach River, it inhabits thick stands of sedge Cyperus, which are absent from the middle Fly sites, on the fringes of the lower river and its bays and inlets (Finch 1980). It is replaced by Clamorous Reed-warbler Acrocephalus stentoreus in other habitats such as the much more extensive Phragmites reedbeds (N. Stronach in litt. 1996). Birds breed during the dry season and may have more catholic habitat requirements in the flooded, non-breeding season.

Threats
Introduced rusa deer Cervus timorensis overgraze and destroy suitable habitat and are thought to be the cause of its absence from Merauke National Park (Coates 1990, K. D. Bishop in litt. 1994, N. Stronach in litt. 1996). Scrub and swamp woodland is encroaching through unknown reasons, perhaps related to introduced deer and pigs (N. Stronach in litt. 1996). Grasslands in Irian Jaya suffer from clearance and drainage for agriculture around transmigration settlements (N. Stronach in litt. 1996).

Conservation Actions Underway
It occurs in the contiguous protected areas of Wasur National Park in Irian Jaya and Tonda Wildlife Management Area in Papua New Guinea.Conservation Actions Proposed
Survey unvisited areas of Trans-Fly and Pulau Dolak. Survey other parts of Wasur National Park. Estimate population densities in known sites. Establish rate and trends of habitat degradation. Investigate effect of deer-grazing. Monitor populations at three sites at least. Monitor populations and habitat effects of deer. Include a species-specific component into the management plan for Wasur National Park and Tonda Wildlife Management Area.

References
Coates, B. J. 1990. The birds of Papua New Guinea, 2: passerines. Dove, Alderley, Australia.

Eastwood, C.; Gregory, P. 1995. Interesting sightings during 1993 & 1994. Muruk 7(3): 128-142.

Finch, B. W. 1980. Rediscovery of the Fly River Grassbird Megalurus albolimbatus in the Bensbach River system, Western Province. Papua New Guinea Bird Society Newsletter 171-172: 6-12.

Gregory, P.; Jaensch, R. 1995. Observations on the Fly River Grassbird Megalurus albolimbatus. Muruk 7(3): 120.

Rand, A. L. 1938. Results of the Archbold expeditions. No, 20. On some passerine New Guinea birds. American Museum Novitates 991.

Further web sources of information
Detailed species accounts from the Threatened birds of Asia: the BirdLife International Red Data Book (BirdLife International 2001).

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
Derhé, M., Gilroy, J., O'Brien, A.

Contributors
Bishop, K., Gregory, P., Stronach, N., Mack, A.

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

Recommended citation
BirdLife International (2014) Species factsheet: Megalurus albolimbatus. Downloaded from http://www.birdlife.org on 20/12/2014. Recommended citation for factsheets for more than one species: BirdLife International (2014) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 20/12/2014.

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.

Key facts
Current IUCN Red List category Vulnerable
Family Sylviidae (Old World warblers)
Species name author (D'Albertis & Salvadori, 1879)
Population size 1500-7000 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 2,400 km2
Country endemic? No
Links to further information
- Additional Information on this species