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 extremely 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.
The global population is suspected to number 5,000,000-49,999,999 mature individuals (Partners in Flight 2022).
The population trend has not been investigated. The only threat known to this forest-dependent species is the loss and degradation of its habitat. Tree cover loss within the range is low (4% over three generations; Global Forest Watch 2022, using Hansen et al.  data and methods disclosed therein). Population declines are therefore likely similarly low; they are here tentatively placed in the band 1-9% over three generations.
Text account compilers
Butchart, S., Ekstrom, J., Symes, A. & Taylor, J.
BirdLife International (2023) Species factsheet: Trogon collaris. Downloaded from http://datazone.birdlife.org/species/factsheet/collared-trogon-trogon-collaris on 03/10/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 03/10/2023.