Justification of Red List category
Population justification
The population is inferred 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.
Trend justification
The population is inferred to be declining owing to ongoing forest loss (Global Forest Watch 2021) and range contraction modelling (Ayebare et al. 2018). Data from Global Forest Watch (2021) suggests that between 2001-2019, this species lost 8.7% of forest cover from its range, and and assuming the population declines at a similar rate, this may equate to a decline of 4.7% over 10 years. Ayebare et al. (2018) estimate that this species will lose 91% of its range between c.2018-2080, based on species distribution modelling. Assuming that the population declines at a similar rate to habitat loss, this would equate to a future loss of 32% over 10 years.
Pseudocalyptomena graueri is known from only two areas in the eastern Democratic Republic of Congo, the Itombwe Mountains and the mountains west of Lake Kivu, and one area in south-west Uganda, Bwindi (Impenetrable) Forest. The species is not considered common in Bwindi Forest, where density is probably one per km2, and recent surveys have been unsuccessful in locating the species in Kahuzi-Biéga National Park (A. Plumptre in litt. 2007).
It inhabits primary rainforest (up to 20 m off ground, but usually in middle strata in Bwindi), and also occurs in forest edge and isolated trees in cleared ground (Keith et al. 1992; M. Carswell in litt. 1999). It feeds on seeds, flowers, buds, fruit, beetles, larvae and snails (Keith et al. 1992). The only recorded nest was found 11 m up in a 20 m tree in the outermost branches overhanging a stream, situated in a valley floor with open shrubby vegetation (Keith et al. 1992). At Bwindi, adults have been seen feeding fledged young in March (M. Carswell in litt. 1999), but also feeding nestlings in July (H. Mugabe in litt. 2016).
Deforestation and forest degradation are the most likely threats throughout its range. Forest in the Itombwe Mountains and Kahuzi-Biéga is under increasing pressure from pastoralists, farmers, pit-sawyers, miners and hunters (Butynski et al. 1997; Hall et al. 1998; Omari et al. 1999). The human population in this volatile area is increasing rapidly and thousands of refugees from Burundi and Rwanda live in camps at the base of Itombwe's eastern escarpment and to the north (Butynski et al. 1997; Hall et al. 1998; Omari et al. 1999). Clearance for agriculture, particularly along the southern and western edges of gallery montane forest, has increased dramatically in the past few years as maize crops have failed, causing famine (Butynski et al. 1997). This species has been identified as highly at risk of range loss due to climate change (Ayebare et al. 2018).
Conservation Actions Underway
It is very well-protected in Bwindi-Impenetrable National Park (T. Butynski in litt. 1999). The Kahuzi-Biéga National Park embraces much habitat west of Lake Kivu, but is under threat (Hall et al. 1998), and the Itombwe Mountains are not protected.
10 cm. Small, rotund, short-tailed bird. Overall leaf-green in colour with blue throat, breast and rump. Voice High-pitched and squeaky twittering. Hints Sluggish in movement when feeding, but fluffs body feathers and shivers and trembles and quivers wings when excited and in display. Usually found at 7-20 m in dense foliage, occurring singly, in pairs, or parties of up to 10, often joining mixed-species flocks (Hall et al. 1998).
Text account compilers
Clark, J.
Contributors
Butynski, T.M., Carswell, M., Ekstrom, J., Evans, M., Mugabe, H., Plumptre, A., Shutes, S., Symes, A., Taylor, J. & Westrip, J.R.S.
Recommended citation
BirdLife International (2024) Species factsheet: Grauer's Broadbill Pseudocalyptomena graueri. Downloaded from
https://datazone.birdlife.org/species/factsheet/grauers-broadbill-pseudocalyptomena-graueri on 23/12/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from
https://datazone.birdlife.org/species/search on 23/12/2024.