Current view: Data table and detailed info
Taxonomic note
Hydrobates leucorhous has been split into H. leucorhous, H. socorroensis and H. cheimomnestes (Handbook of the Birds of the World and BirdLife International 2018). The taxa can be separated only tentatively and on combinations of characters and items of evidence. Using such combinations, Howell (2012) treated both taxa as potentially separate species from Leach’s, using ‘[l.]’ in the scientific name, apparently to indicate the uncertainty involved in that decision. The accounts of the morphological differences between the taxa repeatedly refer to means and inclinations (‘typically’, ‘averages’, ‘generally’, ‘usually’, ‘relatively’, ‘often’, ‘tends to’). Clearly the fact that cheimomnestes breeds at different times of year from socorroensis (and therefore also has a different moult schedule) strongly suggests that two species are involved, but this in itself cannot be the single decisive factor. Moreover, Howell’s (2012) case for the split of socorroensis from leucorhous is hard to discern. In an online post Howell (2015) produced some photographs of cheimomnestes which he used to further his call to split the taxa, which he there described as ‘distinct’. Even so, this new evidence was not different evidence, and nothing was provided which increased the confidence with which the taxa can confidently be discriminated.
In the case of Monteiro’s Storm-petrel H. monteiroi the evidence for separating it as a species included vocal playback experiments that showed a lack of response to calls of Band-rumped Storm-petrel H. castro (see Checklist 1: 372). This, combined with the difference in breeding schedule, has widely clinched approval for the split. It turns out that Ainley (1980) reported in considerable detail on the vocal differences of the two Guadalupe taxa from leucorhous and from each other, although he did not conduct playback experiments to test for responses and the differences of socorroensis and cheimomnestes are not so remarkable. Nevertheless, the differences he found, repeated in summary form in Howell (2012), represent moderately firm evidence to incline the decision on the taxonomic rank of these taxa in favour of species; and accordingly we accept these splits.
Further evidence is nonetheless highly desirable, and could reverse this conclusion, if a large sample of vocalisations were to demonstrate overlap or if birds in burrows were to react to playback. It is to be noted that the tree in Wallace et al. (2017) shows one specimen of socorroensis grouping with cheimomnestes, ‘possibly as a result of recent ancestry and incomplete lineage sorting’ (and NB: ‘these relationships are being investigated further with larger sample sizes (Taylor et al., unpubl.).’).
The generic position of the Leach’s Storm-petrel complex varies among lists. Wallace
et al. (2017), however, are aligned with the
Checklist use of
Hydrobates: ‘Our results… agree with recent taxonomy changes (subsuming
Oceanodroma into genus
Hydrobates…)’.
Taxonomic source(s)
Ainley, D. G. 1980. Geographic variation in Leach's Storm-Petrel. The Auk 97: 837-853.
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.
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.
Howell, S. 2015. First at-sea images of Ainley’s Storm-Petrel—but who cares? Available at: https://leica-nature-observation-blog.com/blog/.
Wallace, S. J., Morris-Pocock, J. A., González-Solís, J., Quillfeldt, P. & Friesen, V. L. 2017. A phylogenetic test of sympatric speciation in the Hydrobatinae (Aves: Procellariiformes). Molec. Phylogen. Evol. 107: 39-47.
IUCN Red List criteria met and history
Red List criteria met
Red List history
| Migratory status |
full migrant |
Forest dependency |
does not normally occur in forest |
| Land-mass type |
|
Average mass |
37 g |
Population justification: In Brooke (2004), the population size for both H. cheimomnestes and H. socorroensis combined was placed at 5,000 pairs (i.e. 10,000 mature individuals). Howell (2012) suggests that the population for this taxon alone is likely no more than a few thousand individuals. Therefore, the population size may be best placed in the range 2,500-9,999 mature individuals.
Trend justification: It is not certain whether invasives, which have impacted species on mainland Guadalupe Island, have made it to the offshore islets, and so their direct impact on the species is uncertain. It is not known whether potential at sea threats have any impact on this species either. Therefore, in the absence of any evidence for any declines the species is tentatively assessed as being stable.
Country/territory distribution
Important Bird and Biodiversity Areas (IBA)
Recommended citation
BirdLife International (2024) Species factsheet: Ainley's Storm-petrel Hydrobates cheimomnestes. Downloaded from
https://datazone.birdlife.org/species/factsheet/ainleys-storm-petrel-hydrobates-cheimomnestes on 21/12/2024.
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 21/12/2024.
