Hydrobates microsoma


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Hydrobates microsoma
Species Authority: (Coues, 1864)
Common Name(s):
English Least Storm-petrel, Least Storm Petrel, Least Storm-Petrel
Halocyptena microsoma Coues, 1864
Oceanodroma microsoma AOU checklist (1998 + supplements)
Oceanodroma microsoma Sibley and Monroe (1990, 1993)
Oceanodroma microsoma SACC (2005)
Oceanodroma microsoma BirdLife International (2004)
Taxonomic Notes: Hydrobates microsoma (del Hoyo and Collar 2014) was previously placed in the genera Oceanodroma and Halocyptena.

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Facilitator/Compiler(s): Butchart, S., Calvert, R. & Ekstrom, J.
This species has a very 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). Despite the fact that the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). The population size is very 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.

Geographic Range [top]

Range Description: This species breeds on islands in the Gulf of California and on the western coast of Baja California (Mexico). Its range stretches from California (USA) to as far south as Colombia and Ecuador1.

Colombia; Costa Rica; Mexico; Panama; United States
Present - origin uncertain:
Ecuador; El Salvador; Guatemala; Nicaragua
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Brooke (2004) estimated the global population to number hundreds of thousands of individuals, possibly millions.
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: This species is marine and often pelagic, mainly occurring over warm waters away from land. Its diet is comprised mostly of small planktonic crustaceans, particularly the larvae of the spiny lobster. It feeds on the wing, by pattering, and by surface-seizing whilst on the water. Breeding starts in June or July, forming colonies on small islands or rocky stacks and nesting in rock crevices (del Hoyo et al. 1992)
Systems: Terrestrial; Marine

Citation: BirdLife International 2012. Hydrobates microsoma. The IUCN Red List of Threatened Species. Version 2015.2. <>. Downloaded on 31 August 2015.
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