Archived 2019 topic: Markham’s Storm-petrel (Hydrobates markhami): request for information.

BirdLife species factsheet for Markham’s Storm-petrel

Markham’s Storm-petrel (Hydrobates markhami) occurs in the tropical zone of the eastern Pacific Ocean. Between July and September, it is found over warm, equatorial waters, while between January and July it moves to cooler waters of the Peru Current and further west (Pyle 1993, Spear and Ainley 2007). It breeds on the Paracas peninsula on the coast of central Peru and in the Atacama Desert of southern Peru and northern Chile (Carboneras 1992, Barros et al. 2019). Markham’s Storm-petrel breeds in dispersed colonies using fissures and holes created by saltpetre deposits for nesting (Tobias et al. 2006, Schmitt et al. 2015, Barros et al. 2019).

Following the recent discovery of several large breeding colonies in the Atacama, the global population was estimated to number c.50,000-60,000 breeding pairs (Schmitt et al. 2015, Barros et al. 2019). This equates to 100,000-120,000 mature individuals, or 150,000-180,000 individuals in total.

The principle threat faced by Markham’s Storm-petrel is the mining of saltpetre from the salt plain on which it nests (Torres-Mura and Lemus 2013, Barros et al. 2019). This has resulted in the loss of considerable amounts of breeding habitat, as it destroys the burrows and crevices in which nests are placed (Schmitt et al. 2015, Barros et al. 2019). Light pollution also represents a significant level of mortality, with 10-20 fresh corpses reported each morning next to a single light close to a breeding colony (Schmitt et al. 2015). It is assumed that fledglings are attracted to the lights of nearby cities during their first flight (Torres-Mura and Lemus 2013, Schmitt et al. 2015). It has been estimated that each year around 20,000 fledglings die because of light pollution, representing 1/3 of the entire cohort (F. Medrano in litt. 2019). Light-pollution was found to be a severe threat to seabirds and Hydrobatidae in particular, which can potentially have a detrimental effect on the overall population size (Rodriguez et al. 2017). Further threats include infrastructure developments (roads, wind farms, power lines) and garbage (Barros et al. 2019).

Markham’s Storm-petrel is currently classified as Data Deficient, as detailed data on population trends have been lacking. Considering the recently obtained information on the breeding colonies and  potential threats, the species may warrant a change in Red List status. Therefore, we present here our reassessment against all criteria for the species.

Criterion A – The population trend of Markham’s Storm-petrel has not been estimated directly. However, it has been suggested that each year, about 20,000 fledglings die after light-induced grounding (Barros et al. 2019). Based on this, we can suspect that the population is in decline. The rate of decline cannot be assessed based on the available information though, as population decline is measured as the decline in mature individuals. Juvenile seabirds generally have a high mortality for various reasons, which is dependent on age, sex and environmental parameters (Fay et al. 2015). It is not clear how many juveniles of Markham’s Storm-petrel die of natural causes each year, or if the reduced population density may even enhance the survival of the remaining fledglings, as has been shown in other seabirds (Fay et al. 2015). As such, it is unclear to which extent the light-induced mortality of juveniles affects the recruitment and the population size of Markham’s Storm-petrels.  

In order to be listed as Vulnerable, Markham’s Storm-petrel would have to undergo a decline of ≥ 30% over three generations. Therefore, information is urgently sought regarding the potential current rate of decline in mature individuals (e.g. within a known colony), to see whether the overall rate of decline in this species is large enough to warrant its listing under Criterion A4e and possibly additionally A3e.

Criterion B – Using a Minimum Convex Polygon, the Extent of Occurrence (EOO) of this species has been calculated as 14 million km2. This is far too large for listing the species as Vulnerable and therefore, Markham’s Storm-petrel may be considered Least Concern under Criterion B1.

The Area of Occupancy (AOO) has not been calculated. Following IUCN Guidelines (IUCN 2001, 2012), the AOO is measured by a 4 km2-grid, to be overlaid over the area of known breeding colonies. We can derive a rough estimate of the AOO based on the population density in the known breeding colonies. For several colonies in Chile, the area has been measured. These include Pampa Chuño (41 ha), Pampa Chaca (6,100 ha) and Pampa Camarones (2,209 ha) in Arica, as well as Pampa La Perdiz (33 ha) (Barros et al. 2019). A large colony in Salar Grande holding c.20,000 pairs has not been measured; however based on the number of breeding pairs we can assume that it covers roughly the same area as the colony in Pampa Chaca (c.6,000 ha). There is no recent information available about the area of the colony in Paracas in Peru; in the 1990s it contained c.2,300-4,600 pairs (Barros et al. 2019). This is about 10-20% of the colony in Pampa Chaca; therefore the colony in Paracas may cover 10-20% of the area of Pampa Chaca, i.e. 600-1,200 ha. Based on this very preliminary estimate, all known colonies may cover c.150-160 km2. Additionally, there are several other colonies in Chile which have not been measured (Barros et al. 2019). Consequently, we can conclude that the AOO of Markham’s Storm-petrel must be larger than 150 km2. This is supported by Barros et al. (2019), who report an AOO of c.250 km2, though no details are given on how this value was derived. We can therefore tentatively assume that the species meets the threshold for listing as Endangered under Criterion B2 (AOO < 500 km2). However, in order to be listed under this criterion, at least two further conditions have to be met.

Based on the size of the breeding colonies, the species cannot be considered severely fragmented sensu IUCN (i.e. most individuals are found in small, isolated subpopulations; IUCN 2001, 2012). The seven known colonies in Chile are subject to a variety of threats, which affect the colonies to a different scale (Barros et al. 2019). The most severe threats to the species are mining, light pollution and infrastructure developments. All these threats represent single events, which are restricted to a very small geographical scale. Per IUCN, a location is defined as a place where one threatening event can quickly eradicate the entire population (IUCN 2001, 2012). Mining only represent a threat to two of the known colonies, both of which extend over 20 and 40 km in length. Each of these colonies therefore most likely consists of a high number of locations. Similarly, light pollution and infrastructural developments, respectively, are affecting only three colonies each, which also contain a high number of locations. Therefore, we can conclude that Markham’s Storm-petrel occurs at > 10 locations and does not meet condition a. In several places throughout the colonies, AOO and habitat quality are observed to be declining due to ongoing mining, garbage pollution and infrastructural development. The species therefore meets conditions b(ii,iii). There is no evidence of a decline in EOO and number of subpopulations and the population decline is only suspected based on a number of fledglings dying each year, and so the species does not meet condition b(i,iv,v). Moreover, there is no evidence of extreme fluctuations, and so condition c is not met.

Overall, even though the species may have a small AOO, it does not meet enough conditions to list it as threatened. On a precautionary basis, it may be considered Near Threatened though, approaching the threshold for listing as threatened under Criterion B2ab(ii,iii).

Criterion C – The population of Markham’s Storm-petrel is estimated to number 100,000-120,000 mature individuals. This is too large to warrant listing the species under Criterion C, and as such, Markham’s Storm-petrel may be considered Least Concern under this criterion.

Criterion D – The population size and range of this species are too large for listing as Vulnerable and therefore, Markham’s Storm-petrel may be considered Least Concern under this criterion.

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 appears that the only criteria where the species might meet the threshold for Vulnerable are A4e, and possibly additionally A3e. To better assess the species against these criteria, we urgently request up-to-date information regarding the rate of decline in mature individuals of Markham’s Storm-petrel.

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.

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

Barros, R.; Medrano, F.; Norambuena, H. V.; Peredo, R.; Silva, R.; de Groote, F.; Schmitt, F. 2019. Breeding phenology, distribution and conservation status of Markham’s Storm-petrel Oceanodroma markhami in the Atacama Desert. Ardea 107: 75-84.

Carboneras, C. 1992. Hydrobatidae (Storm-Petrels). In: del Hoyo, J.; Elliott, A.; Sargatal, J. (ed.), Handbook of the birds of the world, pp. 258-271. Lynx Edicions, Barcelona, Spain.

Fay, R.; Weimerskirch, H.; Delord, K.; Barbraud, C. 2015. Population density and climate shape early-life survival and recruitment in a long-lived pelagic seabird. Journal of Animal Ecology 84: 1423-1433.

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.

Pyle, P. 1993. A Markham’s Storm-Petrel in the northeastern Pacific. Western Birds 24: 108-110.

Schmitt F., R. Barros & H.V. Norambuena. 2015. Markham’s Storm Petrel breeding colonies discovered in Chile. Neotropical Birding 17: 5-10.

Spear, L. B.; Ainley, D. G. 2007. Storm-petrels of the eastern Pacific Ocean: species assembly and diversity along marine habitat gradients. American Ornithologists’ Union, Washington, DC.

Tobias, J. A.; Butchart, S. H. M.; Collar, N. J. 2006. Lost and found: a gap analysis for the Neotropical avifauna. Neotropical Birding 1: 4-22.

Torres-Mura J. C.; Lemus, M. L. 2013. Breeding of Markham’s Storm-Petrel (Oceanodroma markhami, Aves: Hydrobatidae) in the desert of northern Chile. Revista Chilena de Historia Natural 86: 497-499.

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5 Responses to Archived 2019 topic: Markham’s Storm-petrel (Hydrobates markhami): request for information.

  1. Dear committee,

    The following comments were made by a team of the NGO “Red de Observadores de Aves y Vida Silvestre de Chile”, who has been working in natural history and conservation of this species since 2013.

    You suggested that Markham’s storm-petrel could be classified as Vulnerable, under the criteria A3e and A4e, since: “In order to be listed as Vulnerable, Markham’s Storm-petrel would have to undergo a decline of ≥ 30% over three generations. Therefore, information is urgently sought regarding the potential current rate of decline in mature individuals (e.g. within a known colony), to see whether the overall rate of decline in this species is large enough to warrant its listing under Criterion A4e and possibly additionally A3e”.

    We agree that the species doesn’t reach the threshold for being threatened under the criteria “C”, and there is not enough information for the criteria “E”, nevertheless we ask you to consider the following aspects, regarding criteria A, B and D.

    Criteria “A”:

    There is not current raw data on the decline of ≥ 30% over three generations in Chile nor in Peru, but such decline could be inferred or suspected for the next three generations, including the past and the future, since at least 22,000 fledglings are dying each year (so, the criteria A3 or A4 could be used). This 22,000 fledglings are disaggregated between: ~2,000 in the city of Arica (in 2018 season ~1,000 fledglings were rescued without systematic search, and it is very likely at least another ~1,000 fell without being found; this number represents ~5% of the estimated fledglings of the Colony of Arica), ~2,000 in the city of Iquique (in 2018 season >1,000 fledglings were rescued without systematic search, and it is very likely at least another 1,000 fell without being found; this number represents 100% of the colony of Pampa Perdiz and some individuals from the Colony of Salar Grande) and 18,000 in the salt mines and the ports of Salar Grande (a >90% suspected of the breeding colony).

    There is no information of how different is this from the natural mortality, but we infer that some colonies (especially Pampa Perdiz and Salar Grande) could be extinguished in the next decade since there is not recruitment.

    The criteria “e” could apply in both cases (A3e and A4e) since the suspected decline is because of light pollution.

    (our commentary continue in a following post)

  2. (continuation of our commentary)

    Criteria “B”:

    We agree with you, that the species doesn’t reach the threshold in the case of the EOO.
    Respecting the AOO, in any case, is lower than the threshold for “Endangered” (AOO < 500 km2), and especially for “Vulnerable” (AOO < 2,000 km2).
    For applying the criteria B2, at least two additional conditions must be met:
    Condition “a” (severely fragmented population): It seems that the population is not severely fragmented (but there is no actual information about the genes-exchange between the population which breeds between April-February (the population of Paracas, Colonia de Arica and Salar de Quiuña) and the one which breeds between November and June (Pampa La Perdiz, Salar Grande and Salar de Navidad). This topic is going to be studied by our team in the next few years.

    -Condition “a” (number of locations): The number of locations deserves to be revised. As you said, “Per IUCN, a location is defined as a place where one threatening event can quickly eradicate the entire population (IUCN 2001, 2012).” Even though some threats (i.e. salt mining, solar plants, the roads, and the garbage) affects punctual areas of the colonies, and in that case there would be a high number of locations as you proposed, threats such as light pollution, powerlines, and wind farms could affect in just one point to the whole population of a major area, suggesting that should be treated as a location.
    Respecting the light pollution, there is evidence that strong sources of light could attract petrels to a distance of dozens of kilometers (Rodríguez et al 2017), and we have registered distances of 50 kilometers in the case of this species (Silva et al. in prep.). In that case, despite the colonies could be in geographically separated salt flats, just one big source of light can attract most of the fledglings of all the salt flats, and eradicate most of the population.
    Respecting powerlines and wind farms, although there is just basic information about flight paths connecting the sea and inland colonies, it seems like there are specific entrances from where pairs nesting as far as 90 km one from the other would fly inland (Barros et al, 2019). In key places like these, bad positioned powerlines or wind farms could cause the death of thousands of birds and affect in a same event birds nesting as far as mentioned, suggesting that numbers of locations must be treated following conservative criteria.
    There is no recent information about how Paracas works but probably is like in the next places (see below).
    In the case of Arica, where just one big source of light in Pampa Chaca, or over the colony, would attract most of the fledglings of the salt flats. Also, bad located powerlines or windfarms could kill most of the adults and fledglings. In that case, the colony of Arica must be considered as one location.
    In the case of Pampa Quiuña, just one hypothetical light source would affect most of the colony, which could happen even with the installation of a solar plant or because the garbage, since is a small colony.
    In the case of Pampa la Perdiz, probably most of the fledglings are dying right now because of light pollution in the cities of Iquique and Alto Hospicio. In this case, any other specific threat (e.g. a solar plant) would affect most of the colony, since is a small colony.
    The same would happen in the case of the colony of Salar Grande – Río Loa (Barros et al. 2019, Medrano et al. 2019), where currently there are big sources of lights in the salt mines and the ports, and we estimated that most of the fledglings of each cohort are dying there. Also, there was a wind farm proposed near a flight path.
    Following that logical argument, the colony the Arica have to be considered as just one colony. The other colonies are: Paracas, Pampa la Perdiz, Salar Grande, and the recently discovered Salar de Quiuña (Malinarich et al. 2018; Medrano et al. 2019), being five breeding locations (in that case, the species would meet the criteria B2a. There is another breeding site (Salar de Navidad), where just three nests have been recorded (Medrano et al. 2019). Considering this low density, this site should not be considered as a locality.
    Condition “b” (reduction in some aspects): Also, as you put above, “In several places throughout the colonies, AOO and habitat quality are observed to be declining due to ongoing mining, garbage pollution, and infrastructural development. The species, therefore, meets conditions b(ii,iii).”. So, the habitat quality is being degraded and the AOO is reducing its extension.
    As we exposed for the Criteria “A”, there is an inferred and projected decline in the mature individual, so it also reaches the condition “v”.

    In this case, the species met the threshold for being classified as Vulnerable B2ab(ii,iii,v)

    Criteria “D”:

    As was exposed in the Criteria “B”, the species would present five localities, so it met the criteria “D2”.

    So, with all this information, we suggest classifying this species as Vulnerable A3e4eB2ab(ii,v)D2.

    Thanks in advance and looking forward to your reply,
    Red de Observadores de Aves y Vida Silvestre de Chile.

    • Red List Team (BirdLife International) says:

      Thank you for you comment and the additional information you provided. We have now reviewed the issues you raised:

      Criterion A: While we can assume that the population is in decline, we have no information on which to base an estimate of the rate of decline. Therefore, with the currently available information, we cannot assess the species against Criterion A.
      Criterion B: The estimate of the number of locations (and potentially also of the AOO) seems to be overly precautionary. Apart from the colonies in the Atacama reported in Barros et al. (2019) there are several colonies in Paracas, another colony in Salar de Navidad (Medrano et al. 2019) and most likely several more colonies near Antofagasta and along the border of Peru and Chile. The breeding AOO is nevertheless likely small, and we can assume that it meets or approaches the threshold for EN (< 500 km2). Nevertheless, the number of locations likely exceeds the threshold by far. It is only a small proportion of a cohort that is grounded by the light source of Pampa Chaca. It would require many separate light sources to eradicate the entire colony within one generation, and consequently significantly more to affect the other colonies in Chile and Peru as well. Similarly for powerlines that might potentially be placed in the flight path; it is highly unlikely that, even in case that a powerline is being built, it would have the potential to wipe out one colony. The number of locations is consequently very large. Based on the currently available information and using a very precautionary approach, we can however assume that the species approaches the threshold for being listed under Criterion B2ab(iii,v).

  3. Red List Team (BirdLife International) says:

    Preliminary proposals
    Based on available information, our proposal for the 2019 Red List is to pend the decision on this species and keep the discussion open until 2020, while leaving the current Red List category unchanged in the 2019 update.

  4. Red List Team (BirdLife International) says:

    Recommended categorisation to be put forward to IUCN
    Following further review, the recommended categorisation for this species has been changed.
    Markham’s Storm-petrel is now recommended to be listed as Near Threatened, approaching the threshold for listing as threatened under Criterion B2ab(iii,v).
    The final 2019 Red List categories will be published on the BirdLife and IUCN websites in December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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