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 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 has been estimated to number c.920,000-1,400,000 individuals (Wetlands International 2006), while the population in Russia is estimated at <c.100 breeding pairs and <c.50 individuals on migration (Brazil 2009).
The overall trend is uncertain, as some populations are decreasing, while others are stable or increasing (Wetlands International 2006). This species has undergone a large and statistically significant increase over the last 40 years in North America (1500% increase over 40 years, equating to a 101% increase per decade; data for Branta canadensis and B. hutchinsii combined, from Breeding Bird Survey and/or Christmas Bird Count: Butcher and Niven 2007).
The species has a large range, breeding across the tundra of Canada, Alaska (USA), and wintering in southern North America including Mexico, and formerly Japan.
Although hunting and other direct mortality takes a substantial toll, this species has increased its range and population since the 1940s (Mowbray et al. 2002).
Text account compilers
BirdLife International (2019) Species factsheet: Branta hutchinsii. Downloaded from http://www.birdlife.org on 18/10/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 18/10/2019.