Data Zone
Justification of Red List category
This species has an extremely large range and although is distributed patchily and at low density within this range, the spread of confirmed records indicates that it is not restricted to a small area of occupancy, although the area of habitat is declining. The total population size is uncertain, but occurs as multiple subpopulations with density estimates indicating that the western portion totals between 3,000 - 12,000 mature individuals. Despite the fact that the population appears to be decreasing, the decline is not believed to be sufficiently rapid to approach threatened thresholds. For these reasons the species is evaluated as Least Concern. Despite the very large range, its dependence on understory bamboo may expose it to greater risk from fragmentation of intact forest in the future and this requires ongoing monitoring and attention.
Population justification
The global population size has not been formally quantified, but this species is described as rare to uncommon, though difficult to detect due to its preference for dense thickets (Remsen Jr. 2020). The western subpopulation has been studied. Investigation of bamboo associated species in southeastern lowland Peru indicated there were between 1,043-3,961 mature individuals in PN Bahuaja-Sonene and RN Tambopata and up to 8,285 mature individuals within Tambopata province (Lloyd 2004). This represents around one third by area of the western portion of the range, hence a total of between 3,000-12,000 mature individuals for this subpopulation. However, the other subpopulations (Serra dos Carajas and any that remain in Alta Floresta) may well be at far lower densities, and occupy a smaller total area, hence the lower bound of the overall population size may fall below 10,000, although this is an uncertain value. Given the very large area of potential occurrence, a tentative population size of 5,000-30,000 mature individuals is estimated. Assuming that the known sites of occurrence are indeed isolated subpopulations, it can be deduced that the western, presumable largest, subpopulation contains considerably more than 1,000 mature individuals, even should the total population fall below 10,000 mature individuals.
Trend justification
The population trend has not been investigated, but declines are suspected on the basis of large-scale habitat loss.
Within the known range, tree cover loss amounts to 3% over ten years; even assuming a contiguous range across the Amazonian basin tree cover loss would be similarly low at 5% over ten years (Global Forest Watch 2023, using Hansen et al. [2013] data and methods disclosed therein). Due to the species' strong preference for Guadua spp. bamboo thickets (Remsen Jr. 2020) population declines may be steeper than the rate of tree cover loss due to additive impacts of habitat degradation. Nevertheless, it is unlikely that population declines exceed 10% in ten years; they are here tentatively placed in the band 1-9% over ten years. In combination with the apparent recent loss of the species from the well-studied Alta Floresta region a continuing decline in the number of mature individuals can be inferred.
Syndactyla ucayalae is known from a disjunct range from south-east Peru, adjacent Bolivia and Brazil to central Amazonian Brazil. Large portions of the range are very poorly studied, and the species is difficult to detect unless the voice is known, but it is undoubtedly distributed very patchily across this wide area. The largest subpopulation is that centered in the southeast lowlands of Peru, where the number and spread of records indicate that occupancy, while unquantified, is unlikely to be very small. The extent of the possible range to the east follows the 'Arc of deforestation', where Amazonian forest loss rates have been highest, however rates of forest cover loss over the past ten years have been relatively slow, between 3-5% (Global Forest Watch 2023; using Hansen et al. [2013] data and methods disclosed therein). A continuing decline in the extent, area and quality of habitat is accordingly estimated to be taking place. Noting that species' specialism in forest with understory containing Guadua spp. bamboo and need for intact forest, plus the observation that it appears to have been lost from the well-surveyed Alta Floresta region (A. Lees in litt. 2024), a continuing decline in the area of occupancy is inferred. A continuing decline is also inferred in the extent of occurrence due to the loss of habitat at the range edges.
It is rare to locally uncommon to 1,300 m in the undergrowth of lowland evergreen, floodplain and river-edge forest, primarily in or near thickets of Guadua bamboo or cane (Ridgely and Tudor 1994, Kratter 1997, Remsen Jr. 2020).
It appears tolerant of small-scale timber extraction and selective logging. Habitat within its core range is relatively intact, but the region is being opened up for development, with oil/gas extraction and mining, and associated road-building and human colonisation, resulting in further degradation (Dinerstein et al. 1995, H. Lloyd in litt. 1999, Stattersfield et al. 1998). Recent rates of forest loss have been slow within the known occupied range at 3-5% over the past ten years (Global Forest Watch 2023, using Hansen et al. [2013] data and methods disclosed therein).
Conservation Actions Underway
The species occurs in several protected areas across its range. It is listed as Near Threatened at the national level in Peru (SERFOR 2018).
Conservation Actions Proposed
Conduct surveys within and adjacent to the known range to determine its true distribution and abundance. Monitor the population trend. Monitor rates of habitat loss. Effectively protect areas of suitable habitat within the range, in both strictly protected areas and community-led multiple use areas.
Size: 19 cm. Summary: A scarce uniform furnarid with a distinctive large upturned bill. Id: Massive bluish (except blackish on ridge) bill with upturned lower mandible. Above rufescent brown, rufous brown, duskier on crown and wings, rump and tail rufous chestnut. Poorly defined ochraceous supercilium. Underparts orange rufous with faint flammulations on sides of throat and breast. Immature with more conspicuous supercilium and black scalloping on underparts. Similar: Bolivian Recurvebill S. striata is not sympatric. Chestnut-crowned Foliage-gleaner Automolus rufipileatus and Brown-rumped Foliage-gleaner A. melanopezus are similar and occur sympatrically but both lack the massive up-turned bill. Hints: favours areas of Guadua bamboo where it forages singly or in pairs, rarely in association with flocks. Best located by call, song or hammering sounds as it forages. Voice: Frequently given call a distinctive loud repeated "chek"; song a fast sharply ascending series of harsh nasal notes lasting about 5 seconds.
Text account compilers
Martin, R., Hermes, C.
Contributors
Butchart, S., Gilroy, J., Lloyd, H., Mahood, S., Sharpe, C.J., Phalan, B. & Lees, A.
Recommended citation
BirdLife International (2024) Species factsheet: Peruvian Recurvebill Syndactyla ucayalae. Downloaded from
https://datazone.birdlife.org/species/factsheet/peruvian-recurvebill-syndactyla-ucayalae 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.