Hydrobates macrodactylus


Taxonomy [top]

Kingdom Phylum Class Order Family

Scientific Name: Hydrobates macrodactylus
Species Authority: (Bryant, 1887)
Common Name(s):
English Guadalupe Storm-petrel, Guadalupe Storm Petrel, Guadalupe Storm-Petrel
Oceanodroma macrodactyla Bryant, 1887
Taxonomic Notes: Hydrobates macrodactylus (del Hoyo and Collar 2014) was previously placed in the genus Oceanodroma as O. macrodactyla.

Assessment Information [top]

Red List Category & Criteria: Critically Endangered D ver 3.1
Year Published: 2012
Date Assessed: 2012-05-01
Assessor(s): BirdLife International
Reviewer(s): Butchart, S. & Symes, A.
Contributor(s): Howell, S., Keitt, B., Sweet, P. & Tershy, B.
Facilitator/Compiler(s): Anderson, O., Bird, J., Butchart, S., Capper, D., Clay, R., Isherwood, I., Lascelles, B. & Symes, A.
This formerly abundant species has not been recorded since 1912, despite several subsequent searches, and it may well have been driven extinct by feral cats, with declines compounded by nesting habitat destruction by goats. However, it cannot yet be presumed to be Extinct because there have been no thorough surveys of this difficult-to-detect species in the appropriate season since 1906, and relatively recent reports of unidentified storm-petrels calling at night, plus the persistence of Leach's Storm-petrel breeding on the island provide some hope that it may survive. Any remaining population is likely to be tiny, and for these reasons it is treated as Critically Endangered (Possibly Extinct).

Geographic Range [top]

Range Description: Hydrobates macrodactylus may persist on Guadalupe, Mexico, 280 km west of Baja California. It was abundant in 1906, but the last record of a breeding bird was in 1912. Searches in 1922, 1925 and the early 1970s failed to find the species. However, there has been no thorough survey in the appropriate season since 1906. Relatively recent reports of storm-petrels calling at night and the apparent persistence of breeding Leach's Storm-petrel H. leucorhous on the island raises some hope that it may survive, although this is unlikely unless it is able to nest in rock crevices in areas inaccessible to cats (Keitt et al. 2009).

Possibly extinct:
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Any remaining population is assumed to be tiny (numbering fewer than 50 individuals and mature individuals).
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: It nested in burrows at high elevations in soft soil under pines Pinus radiata var. binata and cypress Cupressus guadalupensis groves. Eggs are known to have been laid between early March and late June.

Systems: Terrestrial; Marine

Threats [top]

Major Threat(s): The main cause of its demise is thought to be heavy predation by feral cats, compounded by goats destroying and degrading nesting habitat.

Conservation Actions [top]

Conservation Actions: Conservation Actions Underway
Guadalupe is designated as a Biosphere Reserve (S. N. G. Howell in litt. 1998), but until recently there was little active management (B. Tershy and B. Keitt in litt. 1999). Nearly 35,000 goats were removed in 1970 and 1971 (P. Sweet in litt. 1996), but many remained until 2004 when a comprehensive programme was carried out, resulting in the complete eradication of goats from the island (Garcillán et al. 2008). There is potential to remove other introduced species by 2010 with fundraising for cat eradication underway (B. Tershy and B. Keitt in litt. 1999, Tobias et al. 2006). A grant has been made available to fund searches for the species on Guadalupe (B. Tershy in litt. 2006).

Conservation Actions Proposed
Survey the entire island during the breeding season to ascertain if it is still extant. Eradicate introduced predators and herbivores. Birders on pelagic trips off California should be aware of this species and its identification.

Citation: BirdLife International 2012. Hydrobates macrodactylus. The IUCN Red List of Threatened Species. Version 2015.2. <>. Downloaded on 29 August 2015.
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