Ploceus nicolli


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Ploceus nicolli
Species Authority: Sclater, 1931
Common Name(s):
English Usambara Weaver, Tanzanian Mountain Weaver
French Tisserin de Nicoll

Assessment Information [top]

Red List Category & Criteria: Endangered C2a(i) ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Taylor, J. & Butchart, S.
Contributor(s): Baker, N., Dinesen, L., Hansen, L. & Moyer, D.
Facilitator/Compiler(s): Ekstrom, J., Evans, M., Shutes, S., Starkey, M., Symes, A., Taylor, J.
This species occurs at low densities and is assumed to have a very small, declining and severely fragmented population, with each subpopulation being extremely small. In the light of these factors this species is listed as Endangered.

Geographic Range [top]

Range Description: Ploceus nicolli occurs at low densities in the East and West Usambara, Uluguru and Udzungwa Mountains in Tanzania. In the West Usambaras, the nominate subspecies occurs in small numbers at Shume, Magamba and Mazumbai (N. Baker in litt. 1999). In the East Usambaras, it is fairly common at two sites within the Nilo Forest Reserve (Cordeiro 1998, Seddon et al. 1999b) - probably the subspecies's last remaining stronghold (Seddon et al. 1999b). P. n. anderseni is found in the Uluguru Mountains (three records, all from Uluguru North Forest Reserve (Svendsen and Hansen 1995), but not recorded during surveys in 1999-2001 [Burgess et al. 2002]) and the Udzungwa Mountains, including Udzungwa National Park, Ndundulu Forest and the Nyumbanitu Mountains, as well as in a tiny patch of forest c.95 km east of Iringa and in the Udzungwa Scarp Forest Reserve (D. Moyer in litt. 1999). There is a possible record from the Rubeho Mountains, but this has not been confirmed (Fjeldså et al. 1997). The total population has been guessed to number over 1,000 individuals (Seddon et al. 1999b). However, the population in the Udzungwas alone might number 1,000-2,000 individuals (L. Hansen in litt. 2007), although it has been conservatively guessed at 'some hundred' (Dinesen et al. 2001).

Tanzania, United Republic of
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: The population is estimated to number 1,000-2,499 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 667-1,666 mature individuals, rounded here to 600-1,700 mature individuals.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: It inhabits montane evergreen forest, as well as forest edge (Zimmerman et al. 1996) and disturbed forest (Cordeiro 1998). Birds have also been seen in plantations and in cultivated areas, but only where mature trees still exist (Seddon et al. 1999b). It usually occurs in mixed-species parties, often with P. bicolor, feeding in the upper canopy, gleaning insects from epiphyte-covered branches (Svendsen and Hansen 1995, Cordeiro 1998).

Systems: Terrestrial

Threats [top]

Major Threat(s): The increasing human population throughout its range is clearing or altering forest for agriculture, replacing natural forest with plantations, cutting timber and collecting firewood, resulting in loss, degradation and fragmentation of the species's habitat (Svendsen and Hansen 1995, Cordeiro 1998). Although the main montane forest block (120 km2) in the Ulugurus is protected by its inaccessible terrain, the lower slopes are being steadily cleared. Forest in the Ulugurus declined from c.300 km2 in 1955 to c.230 km2 in 2001, mostly due to clearance for cultivation below 1,600 m (Burgess et al. 2002). In Nilo Forest Reserve, understory cultivation (mainly of cardamom) occurs in c.36% of the forest, and a further 6% is cultivated for arable crops (Cordeiro 1998). Habitat in the Nyumbanitu Mountains, Ukami and Ndundulu Forests and Udzungwa National Park has recently been affected by the clearing of broad tourist trails, allowing easier access by hunters and predatory mammals (L. Hansen in litt. 2007). Aside from this degradation, the species's habitat in the Udzungwas is not seen as being immediately threatened, although pressure is increasing (L. Dinesen in litt. 2007).

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
Conservation action at some sites focuses on assisting local initiatives and increasing the involvement of local communities in forest management (Buckley and Matilya 1998, L. Dinesen in litt. 2007). The Udzungwa localities fall within forest catchment reserves or have national park status (L. Dinesen in litt. 2007).

Conservation Actions Proposed
Conduct a survey to assess the species's population size across its range, and survey the Rubeho Mountains to confirm previous reports of the species's occurrence. Monitor population and habitat trends. Establish a coordinated management scheme for Mt Nilo Forest Reserve and adjacent forest in the East Usambaras (Cordeiro 1998). Improve the management of existing protected areas within the species's range. Increase the area of suitable habitat that is covered by protected areas or community-based forest management.

Citation: BirdLife International 2012. Ploceus nicolli. The IUCN Red List of Threatened Species. Version 2015.2. <>. Downloaded on 04 September 2015.
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