NT
Hawaiian Goose Branta sandvicensis



Taxonomy

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A. and Fishpool, L.D.C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 1: Non-passerines. Lynx Edicions BirdLife International, Barcelona, Spain and Cambridge, UK.

IUCN Red list criteria met and history
Red List criteria met
Critically Endangered Endangered Vulnerable
- - -

Red List history
Year Category Criteria
2021 Near Threatened B2ab(ii,iii,iv,v); C2a(i)
2016 Vulnerable D1
2012 Vulnerable D1
2008 Vulnerable D1
2007 Vulnerable
2004 Vulnerable
2000 Vulnerable
1996 Vulnerable
1994 Vulnerable
1988 Threatened
Species attributes

Migratory status altitudinal migrant Forest dependency Does not normally occur in forest
Land mass type Average mass -
Distribution

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 50,700 medium
Extent of Occurrence breeding/resident (km2) 2,564
Number of locations 4-10 -
Severely Fragmented -
Population and trend
Value Data quality Derivation Year of estimate
No. of mature individuals 1700-2200 good estimated 2018
Population trend Increasing good estimated -
Decline (3 years/1 generation past) - - -
Decline (5 years/1 generation past) - - -
Decline (10 years/1 generation past) - - -
Decline (10 years/3 generation future) - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations 3 - - -
Percentage in largest subpopulation 1-89 - - -
Generation length (yrs) 11.54 - - -

Population justification: Recent population estimates have included 1,754 in 2006, 2,019 in 2007, 1,900 - 1,950 in 2008, 1,877 - 1,927 in 2009, 1,888 - 1,978 in 2010 (USFWS 2011), 2,465-2,555 in 2011 (VanderWerf 2012), 3,039 in 2015 (Amidon 2017), and 2,855 in 2016 (USFWS 2018). In 2018, the population was estimated at 3,252 individuals, including 1,104 on Hawai‘i (including 598 birds relocated from Kaua‘i), 627 on Maui, 37 on Moloka’i, 1,482 on Kaua‘i and 2 on O‘ahu (USFWS 2018).

For some time, all populations were dependent on continued releases of captive birds to persist (USFWS 2004), but releases ceased by the late 2000s (USFWS 2011). The populations on Kaua‘i, Hawai‘i Island and Maui are now considered to be self-sustaining (USFWS 2018). The population on Moloka’i is not yet successfully breeding (USFWS 2019), and so it is excluded from this assessment. In 2011-2016, 640 individuals were removed from a site on Kaua‘i to reduce the risk of bird strike at an airport, and moved to Hawai‘i and Maui (VanderWerf 2012, USFWS 2018).

The total population size of all established subpopulations is here placed in the band 2,600 - 3,300 individuals, roughly equivalent to 1,700 - 2,200 mature individuals.

Although the species is capable of flying between islands (Banko and Elder 1990), it is assumed that subpopulations on separate islands are largely isolated.

Trend justification: Historically, the population declined rapidly, and in 1951, the wild population was estimated at 30 individuals (Smith 1952). Captive breeding and reintroduction efforts began in the 1960s, resulting in an increasing population, although the population size declined sharply in 1981-1982 when releases temporarily ceased, indicating that wild populations were only sustained through continued releases (Black et al. 1991). In 1989 the population size was estimated at 476-555 individuals (Black et al. 1991). This grew to around 600 individuals in 1995 (Black 1995), c.885 in 1998, and c.1,249 individuals in 2004 (USFWS 2004). More recent population estimates have included 1,754 in 2006, 2,019 in 2007, 1,900 - 1,950 in 2008, 1,877 - 1,927 in 2009, 1,888 - 1,978 in 2010 (USFWS 2011), 2,465-2,555 in 2011 (VanderWerf 2012), 3,039 in 2015 (Amidon 2017), 2,855 in 2016 (USFWS 2018) and 3,252 in 2018 (USFWS 2019).

Counts since 2004 have included individuals on Moloka’i, which is not yet considered to be an established population. Nevertheless, the global population size is increasing. The population has grown rapidly on Kaua‘i, where there are no mongooses and there may be more available habitat than on other range islands (USFWS 2018). Populations on Maui and Hawai‘i have remained stable or increased slightly in recent years (VanderWerf 2012, USFWS 2018). A recent analysis of subpopulation trends found that populations at Hawai‘i Volcanoes National Park (Hawai‘i), Maui, Haleakala National Park (Maui), and Kaua‘i were all either increasing or stable (Amidon 2017).


Country/territory distribution
Country/Territory Occurrence status Presence Resident Breeding Non-breeding Passage
USA N Extant Yes

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
USA To be deleted after testing
USA Haleakala
USA Hanalei National Wildlife Refuge
USA Kauai Forests and Uplands
USA Mauna Loa-Kilauea Forests
USA Hamakua Forests
USA Kona Forests
USA Kilauea Point National Wildlife Refuge

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
Artificial/Terrestrial Pastureland suitable resident
Grassland Subtropical/Tropical Dry major resident
Grassland Subtropical/Tropical High Altitude suitable resident
Introduced vegetation suitable resident
Shrubland Subtropical/Tropical High Altitude major resident
Shrubland Subtropical/Tropical Moist suitable resident
Altitude 0 - 2700 m Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Agriculture & aquaculture Annual & perennial non-timber crops - Small-holder farming Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Ecosystem degradation, Ecosystem conversion
Agriculture & aquaculture Livestock farming & ranching - Small-holder grazing, ranching or farming Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Ecosystem degradation, Ecosystem conversion
Biological resource use Hunting & trapping terrestrial animals - Intentional use (species is the target) Timing Scope Severity Impact
Past, Unlikely to Return Whole (>90%) Rapid Declines Past Impact
Stresses
Species disturbance, Species mortality
Climate change & severe weather Droughts Timing Scope Severity Impact
Past, Likely to Return Whole (>90%) Causing/Could cause fluctuations Past Impact
Stresses
Ecosystem degradation, Reduced reproductive success, Species mortality
Climate change & severe weather Habitat shifting & alteration Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Ecosystem degradation, Ecosystem conversion
Climate change & severe weather Storms & flooding Timing Scope Severity Impact
Past, Likely to Return Whole (>90%) Causing/Could cause fluctuations Past Impact
Stresses
Species disturbance, Reduced reproductive success, Species mortality
Energy production & mining Renewable energy Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Ecosystem degradation, Ecosystem conversion, Species mortality
Geological events Volcanoes Timing Scope Severity Impact
Past, Likely to Return Minority (<50%) Rapid Declines Past Impact
Stresses
Ecosystem degradation, Ecosystem conversion, Reduced reproductive success, Species mortality
Human intrusions & disturbance Recreational activities Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species disturbance, Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Bos taurus Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Ecosystem degradation
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Canis familiaris Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Capra hircus Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Ecosystem degradation
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Felis catus Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Species mortality, Other
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Herpestes auropunctatus Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Ovis aries Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Ecosystem degradation
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Rattus exulans Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Rattus norvegicus Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Rattus rattus Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Sus domesticus Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Species disturbance, Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Toxoplasma gondii Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Unspecified species Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Ecosystem degradation, Reduced reproductive success, Species mortality
Residential & commercial development Housing & urban areas Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Ecosystem degradation, Ecosystem conversion

Utilisation
Purpose Primary form used Life stage used Source Scale Level Timing
Food - human - - Non-trivial Recent
Pets/display animals, horticulture - - International Non-trivial Recent

Recommended citation
BirdLife International (2022) Species factsheet: Branta sandvicensis. Downloaded from http://www.birdlife.org on 11/08/2022. Recommended citation for factsheets for more than one species: BirdLife International (2022) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 11/08/2022.