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). The population trend is not known, but the population is not believed to be decreasing sufficiently rapidly to approach the thresholds 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 estimated to number 2 million mature individuals (Partners in Flight 2019).
The population trend is difficult to determine. The species has been expanding its range since 1958 into southern U.S.A. (del Hoyo et al. 2004), but it is unclear whether this trend is continuing.
Text account compilers
Butchart, S. & Ekstrom, J.
BirdLife International (2023) Species factsheet: Tyrannus crassirostris. Downloaded from http://datazone.birdlife.org/species/factsheet/thick-billed-kingbird-tyrannus-crassirostris on 30/05/2023. Recommended citation for factsheets for more than one species: BirdLife International (2023) IUCN Red List for birds. Downloaded from http://datazone.birdlife.org on 30/05/2023.