Peruvian Diving-petrel (Pelecanoides garnotii): revise global status?

BirdLife species factsheet for Peruvian Diving-petrel

Peruvian Diving-petrel (Pelecanoides garnotii) breeds on small offshore islands in Peru and Chile. It excavates deep burrows in thick guano for nesting, but may also burrow in sandy soils or use natural rock crevices. The species used to be numerous in the past, but the population has declined significantly. Intense conservation action and habitat restoration efforts managed to halt the declines and even caused the population to increase again (Fernández et al. 2019). Currently, the population numbers around 12,500 breeding pairs on five islands in Chile and 36,500 pairs on four islands in Peru (Fernández et al. 2019, A. Simeone in litt. 2020), which equates to a total of roughly 50,000 pairs or 100,000 mature individuals.

Most nesting islands are formally protected with restricted access. Potential threats to the species in the breeding colonies include predation by invasive mammals which are present on islands, as well as guano extraction and plans for harbour constructions (Vilina 1992, Jahncke et al. 1999, Cristofari et al. 2019, Fernández et al. 2019). At sea, bycatch by artisanal fisheries represents a potential threat, though its impacts on the population are thought to be negligible (García-Godos and Goya 2006). A higher frequency of El Niño Southern Oscillation (ENSO) events may significantly alter the distribution of prey and reduce the diversity of prey items available to the species.

Peruvian Diving-petrel is currently listed as Endangered under Criterion B2ab(iii) (BirdLife International 2020). However, new information regarding the population trend and distribution range suggests that the species may warrant a change in Red List status. Therefore, it will be re-assessed against all criteria:

Criterion A – The species has undergone severe population declines in the past; however, these declines seem to be historical. Since the 1980s, the species has been increasing (Fernández et al. 2019). It is therefore listed as Least Concern under Criterion A.

Criterion B – The Extent of Occurrence (EOO) for the breeding range is 270,000 km2. This is too large to meet the threshold for listing as threatened under Criterion B1. The Area of Occupancy (AOO) for the breeding range is 184 km2, which meets the threshold for Endangered under Criterion B2. However, in order to be listed as threatened under this criterion, a species needs to fulfil at least two further conditions.

The species was found to form six large subpopulations (Cristofari et al. 2019). It is therefore not severely fragmented sensu IUCN (IUCN Standards and Petitions Committee 2019). Potential threats to the species within their breeding colonies include predation by invasive species and guano extraction (Jahncke et al. 1999, Cristofari et al. 2019); however, the rapid population increase over the last three decades indicates that none of these potential threats had strong impacts on the population size. Furthermore, the species is thought to be safe at sea, as neither bycatch nor ENSO events appear to severely impact the species. To conclude, Peruvian Diving-petrel does not seem to face any threat that can potentially eradicate a large part of the population within one generation time (6.6 years), and thus the number of locations* of occurrence cannot be determined. The species does not fulfil condition a.

Due to intense restoration efforts, habitat on the breeding islands appears safe. Nevertheless, ENSO events and alterations of the sea surface temperature cause a reduction in food availability at sea. Therefore, we can conclude that habitat quality is undergoing a continuing decline. Peruvian Diving-petrel thus meets condition b(iii). There is no evidence of extreme fluctuations in the distribution range or population size, and condition c is not met.

Overall, even though the AOO is small, the species does not meet enough conditions to be listed as threatened. Therefore, Peruvian Diving-petrel may be listed as Near Threatened, approaching the threshold for listing as threatened under Criterion B2b(iii).

Criterion C – The population size of Peruvian Diving-petrel has been estimated at c. 100,000 mature individuals. This is too large to warrant listing as threatened under Criterion C, and thus the species is considered Least Concern under this criterion.

Criterion D – The population size is too large to warrant listing as threatened under Criterion D1. The AOO is too large to meet or approach the threshold for listing as threatened; furthermore, based on current information, the species is not facing any plausible threats that are severe enough to extirpate a large part of the population within the next generation (6.6 years; Bird et al. 2020**). The species cannot be assessed against Criterion D2.

Criterion E – To the best of our knowledge no quantitative analysis of extinction risk has been conducted for this species. Therefore, it cannot be assessed against this criterion.

Therefore, it is suggested that Peruvian Diving-petrel (Pelecanoides garnotii) be listed as Near Threatened, approaching the threshold for listing as threatened under Criterion B2b(iii). We welcome any comments on the proposed listing.

Please note that this topic is not designed to be a general discussion about the ecology of the species, rather a discussion of its Red List status. Therefore, please make sure your comments are relevant to the discussion outlined in the topic. By submitting a comment, you confirm that you agree to the Comment Policy.

*The term ‘location’ refers to a distinct area in which a single threatening event can rapidly affect all individuals of the taxon present, with the size of the location depending on the area covered by the threatening event. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat (IUCN 2001, 2012).

**Bird generation lengths are estimated using the methodology of Bird et al. (2020), as applied to parameter values updated for use in each IUCN Red List for birds reassessment cycle. Values used for the current assessment are available on request. We encourage people to contact us with additional or improved values for the following parameters; adult survival (true survival accounting for dispersal derived from an apparently stable population); mean age at first breeding; and maximum longevity (i.e. the biological maximum, hence values from captive individuals are acceptable).

An information booklet on the Red List Categories and Criteria can be downloaded here and the Red List Criteria Summary Sheet can be downloaded here. Detailed guidance on IUCN Red List terms and definitions and the application of the Red List Categories and Criteria can be downloaded here.

References

Bird, J. P.; Martin, R.; Akçakaya, H. R.; Gilroy, J.; Burfield, I. J.; Garnett, S.; Symes, A.; Taylor, J.; Šekercioğlu, Ç.; Butchart, S. H. M. (2020). Generation lengths of the world’s birds and their implications for extinction risk. Conservation Biology online first view.

BirdLife International. 2020. Species factsheet: Pelecanoides garnotii. http://www.birdlife.org (Accessed 14 April 2020).

Cristofari, R.; Plaza, P.; Fernández, C. E.; Trucchi, E.; Gouin, N.; Le Bohec, C.; Zavalaga, C.; Alfaro-Shigueto, J.; Luna-Joquera, G. 2019. Unexpected population fragmentation in an endangered seabird: The case of the Peruvian diving-petrel. Scientific Reports 9: 2021.

García-Godos, I.; Goya, E. 2006. Diet of the Peruvian Diving Petrel Pelecanoides garnotii at La Vieja Island, Peru, 1997-2000: potential fishery interactions and conservation implications. Marine Ornithology 34: 33-41.

IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K.

IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1. Second edition. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K. www.iucnredlist.org/technical-documents/categories-and-criteria.

IUCN Standards and Petitions Committee. 2019. Guidelines for using the IUCN Red List Categories and Criteria. Version 14. http://www.iucnredlist.org/documents/RedListGuidelines.pdf.

Jahncke, J.; García-Godos, A.; Goya, E. 1999. Diet of the Peruvian Diving-petrel at La Vieja and San Gallan, Peru. Journal of Field Ornithology 70: 71-79.

Fernández, C. E.; Portflitt-Toro, M.; Miranda-Urbina, D.; Plaza, P.; Luna, N.; Luna-Joquera, G. 2019. Breeding abundance and population trend of the Peruvian Diving-petrel Pelecanoides garnotii in Chile: Recovery of an endangered seabird? Bird Conservation International, online first view.

Vilina, Y. A. 1992. Status of the Peruvian Diving-petrel, Pelecanoides garnotii, on Chañaral Island, Chile. Colonial Waterbirds 15: 137-139.

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2 Responses to Peruvian Diving-petrel (Pelecanoides garnotii): revise global status?

  1. Red List Team (BirdLife International) says:

    The window for consultation is now closed. We will analyse and interpret the new information and post a preliminary decision on this species’s Red List status on this page in early July.

    Thank you,
    BirdLife Red List Team

  2. Red List Team (BirdLife International) says:

    Preliminary proposal

    The following decision is based on information provided in interim by Coral Wolf and Nick Holmes (in litt. 2020), and Claudia Fernández et al. (in litt. 2020).

    As previously mentioned, the Peruvian Diving-petrel has seen an increase in its population in recent years, with breeding confined to 8 islands; Corcovado, San Gallán, and La Vieja in Peru and Pan de Azúcar, Grande de Atacama, Choros, Pajaros II, and Fernández Vial in Chile. The largest breeding colonies are moreover found in the La Vieja-San Gallán islands and Choros, harbouring 68% and 24% of the population respectively. All other localities are thought to include smaller colonies. Moreover, habitat protection and eradication programmes on Choros, as well as Chañaral Island has likely contributed to the recent increase of the overall population. However, as noted by C. Fernández et al. (in litt. 2020), the recent increase on Choros peaked in 2013, after which the population saw declines due to unknown reasons. It is here however considered overly precautionary to lever ongoing rapid declines of the global population within a 3-generation period after strong population increases, particularly given the positive impacts of past conservation projects and good opportunities for future projects. At the moment it is unclear whether the population may have undergone a random fluctuation since 2013, with the possibility of population recovery imminent in the coming years. Thus, due to this uncertainty, as well as the under-representation of the overall population, it is untenable in this instance to define future decline based on localised declines alone, but this will be reassessed should rapid declines materialise. In addition to this, whilst threats remain prevalent across the species’s range, including guano extraction, fisheries, and inevitability of recolonization by invasive species, due to an increase in the population, the likelihood of the overall population being driven to extinction is low. Thus, the number of locations (*see definition above) remains unquantified. Nevertheless, assuming that habitat quality is continuing to be impacted, our preliminary proposal for the 2020 Red List would be to adopt the proposed classifications outlined in the initial forum discussion and list the Peruvian Diving-petrel as Near Threatened, nearly meeting Criterion B2b(iii).

    There is now a period for further comments until the final deadline in mid-July, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from the initial proposal.

    The final 2020 Red List categories will be published on the BirdLife and IUCN websites in December 2020/January 2021 (information on the IUCN Red List update process can be found here), following further checking of information relevant to the assessments by both BirdLife and IUCN.

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