Justification of Red List Category
This species has a small, fragmented range, within which habitat loss and/or increased pesticide use are suspected to be causing a continuing decline in its small population. The species is therefore considered Vulnerable. Habitat loss may accelerate with increased agricultural development and this species should be monitored to assess whether its threat status needs to be upgraded.
The population is estimated to number 2,500-9,999 mature 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 3,750-14,999 individuals in total, rounded here to 3,500-15,000 individuals.
The species's population is suspected to be in decline owing to the continued conversion of swamps in the Kilombero river floodplain for cultivation and pasture. The likely rate of decline has not been estimated.
Ploceus burnieri, first discovered in 1986, has a very small range, being confined to the Kilombero river floodplain in south-central Tanzania (Baker and Baker 1990). It has a patchy and restricted distribution within its range, but is abundant in suitable habitat (H. Rainey in litt. 1999).
It occurs in extensive riverside swamps fringed with tall reedbeds Phragmites, generally in areas away from trees (possibly related to competition with the African Golden-Weaver P. subaureus) (H. Rainey in litt. 1999). It has been observed foraging in groups on the ground prior to flooding (Baker and Baker 1990). It may also be found in areas of grassland away from the Kilombero River, and can tolerate some disturbance (Ntongani and Andrew 2013; Rannestad et al. 2015). The diet includes flowering and fruiting grass-heads, as well as dried fish and domestic refuse (H. Rainey in litt. 1999). Nests are in loose groups of up to 20 (occasionally 30), each being attached to a single reed-stem, frequently overhanging water, in areas of seasonal flooding (H. Rainey in litt. 1999). Clutch-size is apparently 1-2 (Baker and Baker 1990).
The extent of dry-season cultivation in the centre of the floodplain is increasing and use of the central portion of the Kilombero Valley by pastoralists is increasing rapidly (H. Rainey in litt. 1999). As well as the resulting habitat loss, dry-season burning, to clear fields and to promote growth of new grass for cattle, may have a negative impact (H. Rainey in litt. 1999). Grazing may also affect habitat directly (H. Rainey in litt. 2007). A expanding area of unknown size in the north of the Kilombero Valley has been converted for large-scale sugar cane cultivation (N. Burgess in litt. 2007, H. Rainey in litt. 2007), with up to 200 km2 predicted to be converted in the near future (H. Rainey in litt. 1999). Individual farmers supply the sugar cane processing plant and are less likely to be limited by any pesticide or planning laws than the industrial plantations (H. Rainey in litt. 2007). Additionally, rice farming is expanding and could affect the species's habitat (H. Rainey in litt. 2007). Increases in pesticide- or fertiliser-use in the catchment may have negative impacts on the species and its habitat (H. Rainey in litt. 1999). However, apparently no studies of the effects of pesticides or fertilisers on wildlife have been carried out (H. Rainey in litt. 2007). While this species may be able to tolerate some habitat disturbance (Ntongani and Andrew 2013), it has such a restricted range that threats could affect a large proportion of the population at once and lead to very rapid declines.
Conservation Actions Underway
The Kilombero Valley has recently been declared a Ramsar site, with funding allocated from the Wildlife Department (N. Burgess in litt. 2007). It was formerly designated a Game Controlled Area, which only restricted the hunting of large animals, and not land-use (e.g. commercial agriculture) that might be deleterious for this species. Game Controlled Areas have been replaced by Wildlife Management Areas. However, the status of the valley is uncertain (N. Burgess in litt. 2007).
14-15 cm. Medium-sized, green-and-yellow weaver. Male nape and underparts bright yellow. Contrasting, small black mask extends only to eye and onto throat, narrowly bordered by chestnut. Dark eye. Female dull version of male, lacks black face. Black bill. Brownish-flesh legs. Similar spp. Northern Masked-weaver P. taeniopterus less bright golden-yellow, more chestnut around black mask. Voice Typical weaver-like squizzling and buzzing sounds.
Text account compilers
Benstead, P., Ekstrom, J., Evans, M., Shutes, S., Starkey, M., Symes, A., Taylor, J. & Westrip, J.
Baker, N., Burgess, N., Rainey, H. & Tye, A.
BirdLife International (2019) Species factsheet: Ploceus burnieri. Downloaded from http://www.birdlife.org on 19/09/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 19/09/2019.