Megalurus albolimbatus 


Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Sylviidae

Scientific Name: Megalurus albolimbatus
Species Authority: (D'Albertis & Salvadori, 1879)
Common Name(s):
English Fly River Grassbird, Fly River Grass Warbler
Identification information: 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.

Assessment Information [top]

Red List Category & Criteria: Vulnerable B1ab(i,ii,iii,v) ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Bishop, K., Gregory, P., Stronach, N. & Mack, A.
Facilitator/Compiler(s): Derhé, M., Gilroy, J. & O'Brien, A.
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.

Previously published Red List assessments:
2008 Vulnerable (VU)
2004 Vulnerable (VU)
2000 Vulnerable (VU)
1996 Vulnerable (VU)
1994 Vulnerable (VU)
1988 Threatened (T)

Geographic Range [top]

Range Description: 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).

Countries occurrence:
Indonesia; Papua New Guinea
Continuing decline in area of occupancy (AOO): Yes
Extreme fluctuations in area of occupancy (AOO): No
Estimated extent of occurrence (EOO) - km2: 2400
Continuing decline in extent of occurrence (EOO): Yes
Extreme fluctuations in extent of occurrence (EOO): No
Number of Locations: 6-10
Continuing decline in number of locations: Unknown
Extreme fluctuations in the number of locations: No
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: 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.
Current Population Trend: Decreasing
Additional data:
Number of mature individuals: 1500-7000 Continuing decline of mature individuals: Yes
Extreme fluctuations: No Population severely fragmented: No
No. of subpopulations: 2-100 Continuing decline in subpopulations: Unknown
Extreme fluctuations in subpopulations: No All individuals in one subpopulation: No

Habitat and Ecology [top]

Habitat and 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.

Systems: Terrestrial; Freshwater
Continuing decline in area, extent and/or quality of habitat: Yes
Generation Length (years): 3.6
Movement patterns: Not a Migrant

Threats [top]

Major Threat(s): Introduced rusa deer Rusa 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 [top]

Conservation Actions: 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.

Citation: BirdLife International. 2012. Megalurus albolimbatus. The IUCN Red List of Threatened Species 2012: e.T22715497A39495645. . Downloaded on 30 November 2015.
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