Ploceus nicolli 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Aves Passeriformes Ploceidae

Scientific Name: Ploceus nicolli Sclater, 1931
Common Name(s):
English Usambara Weaver, Tanzanian Mountain Weaver
French Tisserin de Nicoll
Taxonomic Source(s): del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.
Identification information: 13-14 cm. Medium-sized, nuthatch-like weaver of forest. Most likely to be seen in the upper strata and canopy only. Matt black upperparts. Dark brown, almost black, head with dull yellow forehead and yellowish nuchal patch. Lemon-yellow underparts. Below the blackish bib there is a diffuse orange-brown patch, broadest at its centre. Female similar but with brown head. Bright yellow eye in both sexes. Bill black. Similar spp. Forest Weaver P. bicolor lacks chestnut breast-band and has ivory coloured bill. Voice Soft but rather high pitched si swee-ee. Rather vocal when feeding. Voice not far from that of Grey Cuckoo-Shrike Coracina caesia. Hints Shy. Most frequently seen above 1,400 m in Mazumbai forest, West Usambara Mountains, Tanzania.

Assessment Information [top]

Red List Category & Criteria: Endangered C2a(i) ver 3.1
Year Published: 2016
Date Assessed: 2016-10-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
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. & Westrip, 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.

Previously published Red List assessments:

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).

Countries occurrence:
Tanzania, United Republic of
Additional data:
Continuing decline in area of occupancy (AOO):Yes
Extreme fluctuations in area of occupancy (AOO):NoEstimated extent of occurrence (EOO) - km2:51900
Continuing decline in extent of occurrence (EOO):UnknownExtreme fluctuations in extent of occurrence (EOO):No
Number of Locations:11-100Continuing decline in number of locations:Unknown
Extreme fluctuations in the number of locations:NoLower elevation limit (metres):900
Upper elevation limit (metres):1850
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:The total population has been guessed to number over 1,000 individuals (Seddon et al. 1999b), and possibly over 2,500 individuals, but not more than 5,000 (L. Hansen in litt. 2016). The population in the Udzungwas alone might number 1,000-2,000 individuals (L. Hansen in litt. 2007), although it has also been guessed at 'some hundred' (Dinesen et al. 2001). Therefore, the population is conservatively placed in the range of 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. However, this estimate may warrant increasing in the future in line with possible higher population estimates.

Trend Justification:  The species's forest habitat is being cleared, altered and fragmented for agriculture, plantations and timber extraction (Svendsen and Hansen 1995; Cordeiro 1998), thus the population is suspected to be in decline at an unknown rate.
Current Population Trend:Decreasing
Additional data:
Number of mature individuals:600-1700Continuing decline of mature individuals:Yes
Extreme fluctuations:NoPopulation severely fragmented:Yes
No. of subpopulations:2-100Continuing decline in subpopulations:Unknown
Extreme fluctuations in subpopulations:NoAll individuals in one subpopulation:No

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).

Continuing decline in area, extent and/or quality of habitat:Yes
Generation Length (years):4
Movement patterns:Not a Migrant

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. 2016. Ploceus nicolli. The IUCN Red List of Threatened Species 2016: e.T22719031A94607791. . Downloaded on 19 September 2018.
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