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). The population trend appears to be increasing, and hence the species does not 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 estimated to number > c.1,200,000 individuals (Wetlands International 2006), while the population in Japan has been estimated at <c.50 wintering individuals (Brazil 2009).
This species has undergone a large and statistically significant increase over the last 40 years in North America (160% increase over 40 years, equating to a 27% increase per decade; data from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007).
Text account compilers
Butchart, S., Ekstrom, J.
BirdLife International (2018) Species factsheet: Bucephala albeola. Downloaded from http://www.birdlife.org on 20/02/2018. Recommended citation for factsheets for more than one species: BirdLife International (2018) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 20/02/2018.