EN
Ashy Storm-petrel Hydrobates homochroa



Taxonomy

Taxonomic note
Hydrobates homochroa (del Hoyo and Collar 2014) was previously placed in the genus Oceanodroma.

Taxonomic source(s)
Brooke, M. de L. 2004. Albatrosses and Petrels Across the World. Oxford University Press, Oxford.
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
- A2ce+3ce A2ce+3ce

Red List history
Year Category Criteria
2018 Endangered A2ce+3ce
2016 Endangered A2ce+3ce
2012 Endangered A2ce+3ce
2010 Endangered A2c,e; A3c,e; A4c,e
2008 Endangered A2c,e; A3c,e; A4c,e
2007 Endangered
2005 Endangered
2004 Endangered
2000 Lower Risk/Near Threatened
1994 Lower Risk/Near Threatened
1988 Lower Risk/Least Concern
Species attributes

Migratory status full migrant Forest dependency Does not normally occur in forest
Land mass type Land-mass type - shelf island
Average mass -
Extent of occurrence (EOO)

Estimate Data quality
Extent of Occurrence breeding/resident (km2) 434,000 medium
Extent of Occurrence non-breeding (km2) 205,000 medium
Extent of Occurrence breeding/resident (km2) 1,300 medium
Number of locations 11-100 -
Fragmentation -
Population and trend
Estimate Data quality Derivation Year of estimate
No. of mature individuals 3500-6700 medium estimated 2000
Population trend Decreasing medium 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) 50-79 - - -
Decline (10 years/3 generation past and future) - - -
Number of subpopulations - - -
Largest subpopulations - - -
Generation length (yrs) 16 - - -

Population justification: The population is estimated to number 5,200-10,000 individuals, equivalent to 3,500-6,700 mature individuals.

Trend justification: A study on the South Farallon Islands found declines in breeding birds of 42% in 1972-1992 (Sydeman et al. 1998), equivalent to c.23% in 10 years or 78% over three generations, and declines in reproductive success have also been noted on Southeast Farallon Island. On Santa Cruz Island, nest-site monitoring during 1995-2006 showed declines in the number of breeding birds at two of five monitored sites (S. Wolf in litt. 2007). Declines are thought to have been driven by increased levels of predation and pollutants, though it may have been exaggerated by consecutive years of abnormal sea-surface temperatures leading to reduced colony attendance.


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

Important Bird and Biodiversity Areas (IBA)
Country/Territory IBA Name
Mexico Islas Coronado
USA Channel Islands - Northern
USA Farallon Islands
USA Point Conception 120W34N
USA Point Reyes - Outer

Habitats & altitude
Habitat (level 1) Habitat (level 2) Importance Occurrence
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
Rocky areas major breeding
Altitude   Occasional altitudinal limits  

Threats & impact
Threat (level 1) Threat (level 2) Impact and Stresses
Climate change & severe weather Storms & flooding Timing Scope Severity Impact
Future Minority (<50%) Slow, Significant Declines Low Impact: 3
Stresses
Ecosystem degradation, Reduced reproductive success
Human intrusions & disturbance Recreational activities Timing Scope Severity Impact
Ongoing Minority (<50%) Negligible declines Low Impact: 4
Stresses
Species disturbance, Reduced reproductive success
Invasive and other problematic species, genes & diseases Invasive non-native/alien species/diseases - Mus musculus Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant 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 Minority (<50%) Rapid Declines Medium Impact: 6
Stresses
Reduced reproductive success
Invasive and other problematic species, genes & diseases Problematic native species/diseases - Athene cunicularia Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Problematic native species/diseases - Larus occidentalis Timing Scope Severity Impact
Ongoing Majority (50-90%) Slow, Significant Declines Medium Impact: 6
Stresses
Species mortality
Invasive and other problematic species, genes & diseases Problematic native species/diseases - Tyto alba Timing Scope Severity Impact
Ongoing Minority (<50%) Slow, Significant Declines Low Impact: 5
Stresses
Species mortality
Pollution Agricultural & forestry effluents - Herbicides and pesticides Timing Scope Severity Impact
Past, Unlikely to Return Majority (50-90%) Slow, Significant Declines Past Impact
Stresses
Ecosystem degradation, Reduced reproductive success, Species mortality
Pollution Excess energy - Light pollution Timing Scope Severity Impact
Ongoing Minority (<50%) Unknown Unknown
Stresses
Species disturbance, Species mortality
Pollution Industrial & military effluents - Oil spills Timing Scope Severity Impact
Ongoing Majority (50-90%) Negligible declines Low Impact: 5
Stresses
Ecosystem degradation, Reduced reproductive success, Species mortality

Recommended citation
BirdLife International (2019) Species factsheet: Hydrobates homochroa. Downloaded from http://www.birdlife.org on 07/12/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 07/12/2019.