• Summary
• Text account
• Data table and detailed info
• Distribution map
• Reference and further resources

Taxonomic source(s)
del Hoyo, J., Collar, N.J., Christie, D.A., Elliott, A., Fishpool, L.D.C., Boesman, P. and Kirwan, G.M. 2016. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Volume 2: Passerines. Lynx Edicions and BirdLife International, Barcelona, Spain and Cambridge, UK.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
A2bcde+3bcde+4bcde; C2a(ii)	A2bcde+3bcde+4bcde; B1ab(i,ii,iii,v); C2a(i,ii); D	A2bcde+3bcde+4bcde; B1ab(i,ii,iii,v); C1+2a(i,ii); D1+2

Red List history

Year	Category	Criteria
2018	Critically Endangered	A2bcde+3bcde+4bcde; C2a(ii)
2016	Critically Endangered	A2bcde+3bcde+4bcde; B1ab(i,ii,iii,iv,v); C2a(ii)
2015	Critically Endangered	A2bcde+3bcde+4bcde;C2a(i,ii)
2013	Critically Endangered	A2bcde+3bcde+4bcde;C2a(i,ii)
2012	Critically Endangered	A2bcde+3bcde+4bcde;C2a(i,ii)
2010	Critically Endangered	A2b,c,d,e; A3b,c,d,e; A4b,c,d,e; C2a(ii)
2009	Critically Endangered	A2b,c,d,e; A3b,c,d,e; A4b,c,d,e
2008	Critically Endangered
2004	Endangered
2000	Endangered
1996	Critically Endangered
1994	Critically Endangered
1988	Threatened

Migratory status	not a migrant	Forest dependency	high
Land-mass type		Average mass	-

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	120 km2	medium
Number of locations	1	-
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	50-249 mature individuals	good	estimated	2016
Population trend	decreasing	medium	estimated	1988-2010
Rate of change over the past 10 years/3 generations (longer of the two periods)	80-100%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	80-100%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	80-100%	-	-	-
Generation length	7.3 years	-	-	-
Number of subpopulations	1	-	-	-
Percentage of mature individuals in largest subpopulation	100%	-	-	-

Population justification: In 2013-14, Kroner and Ha (2017) recorded 46 breeding pairs with a potential eight more pairs in unsurveyed areas. They estimated the total population to be only 178 individuals. In 2012, Camp et al. (2015) estimated the population to be 81 individuals (95% CI = 30-202), and Faegre et al. (2016) estimated 50 breeding pairs in the 2015-2016 breeding season. Therefore, the population size is placed here in the range 50-249 mature individuals.

Trend justification: Surveys between 1982 and 2012 have revealed an extremely rapid population decline. The population is estimated to have declined by over 80% over the past three generations (22 years).

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Guam (to USA)	extinct	native	yes
Northern Mariana Islands (to USA)	extant	native	yes

Country/Territory	IBA Name
Guam (to USA)	Guam National Wildlife Refuge
Northern Mariana Islands (to USA)	Rota

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Forest	Subtropical/Tropical Moist Lowland	major	resident
Altitude		Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Agriculture & aquaculture	Annual & perennial non-timber crops - Agro-industry farming	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Rapid Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Biological resource use	Hunting & trapping terrestrial animals - Persecution/control	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Rapid Declines		Medium Impact: 6
		Stresses Species mortality
Climate change & severe weather	Habitat shifting & alteration	Timing		Scope		Severity		Impact
		Future		Whole (>90%)		Unknown		Unknown
		Stresses Indirect ecosystem effects, Ecosystem degradation
Climate change & severe weather	Storms & flooding	Timing		Scope		Severity		Impact
		Past, Likely to Return		Majority (50-90%)		Rapid Declines		Past Impact
		Stresses Ecosystem degradation, Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Boiga irregularis	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Very Rapid Declines		High Impact: 8
		Stresses Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Dicrurus macrocercus	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Very Rapid Declines		High Impact: 8
		Stresses Competition
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Felis catus	Timing		Scope		Severity		Impact
		Ongoing		Whole (>90%)		Very Rapid Declines		High Impact: 9
		Stresses Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Named species	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 - Varanus indicus	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Very Rapid Declines		High Impact: 8
		Stresses Reduced reproductive success
Invasive and other problematic species, genes & diseases	Problematic native species/diseases	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Rapid Declines		Medium Impact: 6
		Stresses Reduced reproductive success, Species mortality
Residential & commercial development	Housing & urban areas	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Rapid Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion
Residential & commercial development	Tourism & recreation areas	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Rapid Declines		Medium Impact: 6
		Stresses Ecosystem degradation, Ecosystem conversion

Purpose	Scale
Pets/display animals, horticulture	international
Pets/display animals, horticulture	international

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Recommended citation
BirdLife International (2024) Species factsheet: Mariana Crow Corvus kubaryi. Downloaded from https://datazone.birdlife.org/species/factsheet/mariana-crow-corvus-kubaryi on 22/11/2024.
Recommended citation for factsheets for more than one species: BirdLife International (2024) IUCN Red List for birds. Downloaded from https://datazone.birdlife.org/species/search on 22/11/2024.