Data Zone
Justification of Red List category
This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km² combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size has not been quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). For these reasons the species is evaluated as Least Concern.
Population justification
This is a poorly known species and no population estimates are available. It appears to be uncommon, and the population may be relatively small (Remsen and Sharpe 2020). Based on the paucity of records, it is precautionarily suspected that the population numbers between 10,000 and 19,999 mature individuals, but an accurate quantification of the population size is urgently needed.
Trend justification
The species is suspected to be in decline as forested habitat within the range is lost, degraded and fragmented.
Over the past ten years, roughly 6% of tree cover has been lost from the range, but since 2016 this rate has been increasing to 8% over ten years (Global Forest Watch 2021, using Hansen et al. [2013] data and methods disclosed therein). Given its high forest-dependency and its susceptibility to fragmentation and edge effects, population declines are likely faster than the rate of tree cover loss suggests, and are therefore here tentatively placed in the band 10-19% over ten years.
Cranioleuca muelleri is endemic to the east Amazon River, Brazil. It ranges from east Amazonas to south Amapá and Mexiana Island (del Hoyo et al. 2003).
This species inhabits seasonally flooded 'várzea' forest, where it is typically found in the undergrowth or mid-story, at elevations of 0-200 m. Even though it can occasionally be found on floodplain cattle pastures, it shows little tolerance of converted and degraded habitats (D. M. Lima in litt. 2022). The species feeds on arthropods. The nest has been described as a globular mass of sticks, placed in a tree, though this report is unconfirmed (del Hoyo et al. 2003, Remsen and Sharpe 2020).
The species depends on mature forests and only shows low tolerance of habitat degradation (D. M. Lima in litt. 2022). It is therefore thought likely to be particularly susceptible to fragmentation and edge effects, and the primary threat is accelerating deforestation in the Amazon basin as land is cleared for cattle ranching and soy production, facilitated by expansion of the road network (Soares-Filho et al. 2006, Bird et al. 2011, A. Lees in litt. 2011). Changes to the Brazilian Forest Code reduced the percentage of land a private landowner is legally required to maintain as forest (including, critically, a reduction in the width of forest buffers alongside perennial steams) and included an amnesty for landowners who deforested before July 2008 (Bird et al. 2011).
Conservation Actions Underway
The species occurs within Anavilhanas National Park (Remsen and Sharpe 2020).
Conservation Actions Proposed
Survey to accurately quantify the population size and trend. Research the species's biology, ecology and subpopulation structure. Monitor the population trend. Monitor rates of habitat loss.
Expand the protected area network to effectively protect key sites. Effectively manage protected areas, utilising emerging opportunities to finance protected area management with the joint aims of reducing carbon emissions and maximizing biodiversity conservation. Incentivise conservation on private lands through expanding market pressures for sound land management and preventing forest clearance on lands unsuitable for agriculture (Soares-Filho et al. 2006).
14-15 cm. Brown spinetail with scaly-looking underparts. Rufous crown, wings and tail, with rich dark brown back and rump. Narrow pale supercilium. Chin, throat, breast and belly white with dark brown feather tips, giving scaled appearance. Legs and feet are an olive-tinged yellow-green colour. Upper mandible blackish, lower mandible pinkish grey, both fading to pale at end.
Text account compilers
Hermes, C.
Contributors
Butchart, S., Ekstrom, J., Khwaja, N., Lees, A., Lima, D., Sharpe, C.J. & Symes, A.
Recommended citation
BirdLife International (2024) Species factsheet: Scaled Spinetail Cranioleuca muelleri. Downloaded from
https://datazone.birdlife.org/species/factsheet/scaled-spinetail-cranioleuca-muelleri on 23/11/2024.
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 23/11/2024.