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 fewer than 170 million mature individuals (Partners in Flight 2019).
The species is undergoing a moderate decline (Partners in Flight 2019). The rate of the decline has not been assessed; together with the recently split San Benito Sparrow (Passerculus sanctorum), Belding's Sparrow (P. guttatus) and Large-billed Sparrow (P. rostratus), the decline amounted to an average rate of 1.3% per year between 1970 and 2017 (Partners in Flight 2019). Short-term trends suggest a moderate decline of 18% over the past ten years (Pardieck et al. 2018). As Savannah Sparrow occupies a much larger range than the recently split species, it is conceivable that it accounts for a large proportion of the observed decline. Thus, 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
Wheatley, H., Hermes, C.
Butchart, S. & Ekstrom, J.
BirdLife International (2022) Species factsheet: Passerculus sandwichensis. Downloaded from http://www.birdlife.org on 17/08/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 17/08/2022.