Black-billed Cuckoo Coccyzus erythropthalmus


Justification of Red List Category
This species has an extremely 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 is very large, and hence does not 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
The global population is inferred to number 880,000 mature individuals (Partners in Flight 2020).

Trend justification
The species has been undergoing a large, significant decline between 1970 and 2017 (Partners in Flight 2019). Short-term trends suggest that the population declined by 27% over the past ten years (Pardieck et al. 2018). Population densities however seem to fluctuate considerably over time in relation to caterpillar outbreaks (Hughes 2020, see also long-term data from Pardieck et al. 2018). Given the uncertainty, the species is tentatively considered to be in decline, but the rate of decline is not considered to approach the threshold for Vulnerable over the relevant three generation time periods for this assessment.


Text account compilers
Hermes, C.

Butchart, S., Ekstrom, J. & Palmer-Newton, A.

Recommended citation
BirdLife International (2022) Species factsheet: Coccyzus erythropthalmus. Downloaded from on 26/09/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from on 26/09/2022.