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

Taxonomic note
Hydrobates leucorhous has been split into H. leucorhous, H. socorroensis and H. cheimomnestes (which see) (Handbook of the Birds of the World and BirdLife International 2018), based on the proposal of Howell (2012).

Taxonomic source(s)
Handbook of the Birds of the World and BirdLife International. 2018. Handbook of the Birds of the World and BirdLife International digital checklist of the birds of the world. Version 3. Available at: https://datazone.birdlife.org/userfiles/file/Species/Taxonomy/HBW-BirdLife_Checklist_v3_Nov18.zip.
Howell, N. G. 2012. Petrels, Albatrosses, and Storm-Petrels of North America: A Photographic Guide. Princeton University Press, Princeton, New Jersey, USA.

Red List criteria met

Critically Endangered	Endangered	Vulnerable
-	-	A2bce+3bce+4bce

Red List history

Year	Category	Criteria
2018	Vulnerable	A2bce+3bce+4bce
2016	Not Recognised
2012	Not Recognised
2008	Not Recognised
2004	Not Recognised
2000	Not Recognised
1994	Not Recognised
1988	Not Recognised

Migratory status	full migrant	Forest dependency	does not normally occur in forest
Land-mass type		Average mass	37 g

	Estimate	Data quality
Extent of Occurrence (breeding/resident)	337,000,000 km2	medium
Severely fragmented?	no	-

	Estimate	Data quality	Derivation	Year of estimate
Population size	6700000-8300000 mature individuals	medium	estimated	2016
Population trend	decreasing	-	estimated	1997-2036
Rate of change over the past 10 years/3 generations (longer of the two periods)	30-40%	-	-	-
Rate of change over the future 10 years/3 generations (longer of the two periods)	30-40%	-	-	-
Rate of change over the past & future 10 years/3 generations (longer of the two periods)	30-40%	-	-	-
Generation length	13 years	-	-	-

Population justification: Brooke (2004) estimated the global population to number >20,000,000 individuals.  Based on the compilation of available data the current population comprises 6.7-8.3 million breeding pairs; 40-48% of these breed in the Atlantic basin and 52-60% in the Pacific. Throughout the western Atlantic (>90% of basin total), populations are declining, including at Baccalieu Island, Newfoundland, Canada, home to the largest colony. The population at Baccalieu Island, estimated at 3.3 million breeding pairs in 1984 (Sklepkovych and Montevecchi 1989), had declined to 2.02 million pairs by 2013 (Environment Canada unpublished data), and the former second and third regionally largest colonies have declined by >50% since the late 1990s (Wilhelm et al. 2015, Environment Canada unpublished data). In the eastern Atlantic, the population at St. Kilda is also declining, this being the largest colony in the UK and Ireland (Newson et al. 2008).  Population trends in the Pacific are less well known. In Alaska, where Leach’s Hydrobates leucorhous and Fork-tailed Storm-petrels H. furactus are largely combined for monitoring purposes, population trends are stable or increasing (Slater and Byrd 2009, Dragoo et al. 2016), the large population at Daikoku Island, Japan may have declined since 1982, while trends of western North American and Russian populations are unknown. Despite these knowledge gaps, compiling available data collected between 1977 and 2016, representing 75-80% of the global population (including Europe, eastern North America, and Japan), points to a decline of ≥30% over three generations (39 years, based on a generation length estimated by BirdLife to be 13 years).

Definitive information on Leach’s Storm-petrel population decline comes mainly from colonies within the Atlantic basin.  Recent genetics research indicates that while there is no genetic structure among Atlantic colonies, populations within the Atlantic and the Pacific are genetically distinct (Bicknell et al. 2012).  Evidence of movement of pre-breeding birds among colonies within the Atlantic, led to the conclusion that North Atlantic birds may be operating as a metapopulation and that management of this species may be best viewed at an oceanic scale (Bicknell et al. 2012, 2014).

Trend justification: Data collected from 1977 to 2016 representing 75-80% of the global population, points to a decline of ≥30% over three generations (Huntingdon et al. 1996, Lormee et al. 2012, BirdLife International 2015, Environment Canada unpublished data, Japanese Ministry of Environment, unpublished data). The cause(s) of declines are unknown, but are likely multi-faceted and further research is needed to inform conservation actions.

Country/Territory	Presence	Origin	Resident	Breeding visitor	Non-breeding visitor	Passage migrant
Algeria	extant	vagrant
Angola	extant	native
Anguilla (to UK)	extant	uncertain
Antarctica	extant	vagrant
Antigua and Barbuda	extant	native
Argentina	extant	native
Australia	extant	vagrant
Austria	extant	vagrant
Bahamas	extant	native
Barbados	extant	native
Belgium	extant	vagrant
Belize	extant	uncertain
Benin	extant	uncertain
Bermuda (to UK)	extant	native				yes
Bonaire, Sint Eustatius and Saba (to Netherlands)	extant	native
Brazil	extant	native			yes
Cameroon	extant	uncertain
Canada	extant	native		yes
Cape Verde	extant	native			yes
Cayman Islands (to UK)	extant	uncertain
China (mainland)	extant	native
Colombia	extant	uncertain
Congo	extant	uncertain
Congo, The Democratic Republic of the	extant	uncertain
Costa Rica	extant	native			yes
Côte d'Ivoire	extant	uncertain
Cuba	extant	native
Curaçao (to Netherlands)	extant	native
Denmark	extant	native				yes
Dominica	extant	native
Dominican Republic	extant	native
Ecuador	extant	native
Egypt	extant	vagrant
El Salvador	extant	uncertain
Equatorial Guinea	extant	uncertain
Estonia	extant	vagrant
Faroe Islands (to Denmark)	extant	native		yes
Finland	extant	vagrant
France	extant	native				yes
French Guiana	extant	native
French Polynesia	extant	native
French Southern Territories	extant	uncertain
Gabon	extant	uncertain
Gambia	extant	vagrant
Germany	extant	vagrant
Ghana	extant	vagrant
Gibraltar (to UK)	extant	vagrant
Greenland (to Denmark)	extant	native			yes
Grenada	extant	uncertain
Guadeloupe (to France)	extant	native			yes
Guam (to USA)	extant	native			yes
Guatemala	extant	native
Guinea	extant	uncertain
Guinea-Bissau	extant	uncertain
Guyana	extant	native
Haiti	extant	native
Honduras	extant	native
Iceland	extant	native		yes
Ireland	extant	native	yes
Israel	extant	native			yes
Italy	extant	vagrant
Jamaica	extant	vagrant
Japan	extant	native
Kenya	extant	vagrant
Kiribati	extant	native
Latvia	extant	vagrant
Lebanon	extant	vagrant			yes
Liberia	extant	native
Luxembourg	extant	vagrant
Maldives	extant	vagrant
Malta	extant	vagrant
Marshall Islands	extant	native			yes
Martinique (to France)	extant	native
Mauritania	extant	native
Mexico	extant	native
Micronesia, Federated States of	extant	uncertain
Montserrat (to UK)	extant	native
Morocco	extant	native
Namibia	extant	native			yes
Nauru	extant	uncertain
Netherlands	extant	native			yes
New Zealand	extant	vagrant
Nicaragua	extant	uncertain
Nigeria	extant	uncertain
Northern Mariana Islands (to USA)	extant	native			yes
Norway	extant	native		yes
Palestine	extant	native			yes
Panama	extant	uncertain
Peru	extant	uncertain
Poland	extant	vagrant
Portugal	extant	native			yes
Puerto Rico (to USA)	extant	native
Russia	extant	native	yes
Russia (Asian)	extant	native
São Tomé e Príncipe	extant	uncertain
Senegal	extant	native
Seychelles	extant	native
Sierra Leone	extant	vagrant
Sint Maarten (to Netherlands)	extant	native
South Africa	extant	native			yes
Spain	extant	native			yes
St Helena (to UK)	extant	native
St Kitts and Nevis	extant	native
St Lucia	extant	native
St Martin (to France)	extant	native
St Pierre and Miquelon (to France)	extant	native		yes		yes
St Vincent and the Grenadines	extant	native
Sudan	extant	vagrant			yes
Suriname	extant	native
Sweden	extant	vagrant
Switzerland	extant	vagrant
Togo	extant	uncertain
Trinidad and Tobago	extant	native
Turks and Caicos Islands (to UK)	extant	native
Tuvalu	extant	uncertain
United Arab Emirates	extant	uncertain
United Kingdom	extant	native		yes		yes
United States Minor Outlying Islands (to USA)	extant	native			yes
Uruguay	extant	vagrant			yes
USA	extant	native		yes
Venezuela	extant	native
Virgin Islands (to UK)	extant	native			yes
Virgin Islands (to USA)	extant	native			yes
Western Sahara	extant	uncertain

Country/Territory	IBA Name
Canada	Baccalieu Island
Canada	Bon Portage Island
Canada	Corbin Island
Canada	Country Island Complex
Canada	Duke of Edinburgh Ecological Reserve
Canada	Gillam Island
Canada	Green Island
Canada	Solander Island and Brooks Bay
Canada	Witless Bay Islands
Iceland	Vestmannaeyjar
Ireland	Stags of Broadhaven
Japan	Daikoku islet
Japan	Eastern Hokkaido - Marine
Russia (Asian)	Kuril islands (between Urup and Paramushir)
St Pierre and Miquelon (to France)	Grand Colombier Island
United Kingdom	Flannan Isles
United Kingdom	Foula
United Kingdom	North Rona and Sula Sgeir
United Kingdom	North Sutherland Coastal Islands
United Kingdom	Ramna Stacks and Gruney
United Kingdom	St Kilda
USA	Buldir Island Colony
USA	Cherni Island Complex Colonies
USA	Forrester Island Colonies
USA	Goat Island NWR
USA	Mack Reef
USA	Semidi Islands Colonies
USA	St Lazaria Island Colony
USA	Umnak Pass Colonies
USA	Whalehead Island NWR

Habitat (level 1)	Habitat (level 2)	Importance	Occurrence
Marine Coastal/Supratidal	Sea Cliffs and Rocky Offshore Islands	major	breeding
Marine Intertidal	Rocky Shoreline	major	breeding
Marine Neritic	Pelagic	major	non-breeding
Marine Neritic	Pelagic	major	breeding
Marine Oceanic	Epipelagic (0-200m)	major	non-breeding
Marine Oceanic	Epipelagic (0-200m)	major	breeding
Altitude		Occasional altitudinal limits

Threat (level 1)	Threat (level 2)	Impact and Stresses
Human intrusions & disturbance	Work & other activities	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Species disturbance, Reduced reproductive success
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Felis catus	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Rapid Declines		Medium Impact: 6
		Stresses Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Mus musculus	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Unknown		Unknown
		Stresses Reduced reproductive success
Invasive and other problematic species, genes & diseases	Invasive non-native/alien species/diseases - Unspecified species	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Rapid Declines		Medium Impact: 6
		Stresses Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases	Problematic native species/diseases - Catharacta skua	Timing		Scope		Severity		Impact
		Ongoing		Minority (<50%)		Slow, Significant Declines		Low Impact: 5
		Stresses Reduced reproductive success, Species mortality
Invasive and other problematic species, genes & diseases	Problematic native species/diseases - Larus argentatus	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Slow, Significant Declines		Medium Impact: 6
		Stresses Reduced reproductive success, Species mortality
Pollution	Industrial & military effluents - Oil spills	Timing		Scope		Severity		Impact
		Ongoing		Majority (50-90%)		Unknown		Unknown
		Stresses Ecosystem degradation, Reduced reproductive success, Species mortality

---

Recommended citation
BirdLife International (2024) Species factsheet: Leach's Storm-petrel Hydrobates leucorhous. Downloaded from https://datazone.birdlife.org/species/factsheet/leachs-storm-petrel-hydrobates-leucorhous on 22/12/2024.
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 22/12/2024.