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.
The global population size has not been quantified, but prior to being split from Z. petersi the species was described as uncommon to common (del Hoyo et al. 2004).
Deforestation has been severe in parts of this species's range (del Hoyo et al. 2004), thus the population is suspected to be in decline.
Text account compilers
Butchart, S., Ekstrom, J. & Wheatley, H.
BirdLife International (2019) Species factsheet: Zimmerius improbus. Downloaded from http://www.birdlife.org on 20/11/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 20/11/2019.