Justification of Red List Category
This species is precautionarily maintained as Vulnerable. Existing demographic studies of populations in France and Malta indicate a population decline, caused by low breeding success due to predation by introduced mammals and low adult survival owing to fisheries bycatch and predation. However, some more recent studies have shown population increases and there may be large as yet undiscovered colonies in the Eastern Mediterranean or the Black Sea. If further study and monitoring provide evidence of large stable or increasing populations, the species may warrant downlisting in the future.
Figures point to a total of 15,337-30,519 pairs, roughly equating to 46,000-92,000 individuals, based on a population assessment covering the species's entire range (Derhé 2012). However, this number is at odds with preliminary counts conducted in early February when c. 75,000-90,000 individuals have been recorded migrating through the Bosporus [J. Tavares and D. Sahin. in litt. 2012, D. Sahin in litt. 2015]), at a time when most breeders are already around their colonies in Malta, France, and Italy. More surveys are urgently needed to confirm breeding population sizes, particularly in the Aegean Sea and in Turkey.
Extremely low breeding success has been reported at several important colonies, particularly in Italy (Baccetti et al. 2009), as well as adult survival probabilities (across the western Mediterranean) that are currently too low to maintain stable populations (Oppel et al. 2011). There is evidence of both recent and historical colony extinctions, with eleven colonies having been reported extinct in the last 60 years (Bourgeois and Vidal 2008, N. Baccetti in litt. 2011, Cadiou 2015). The trends of populations in Albania, Algeria, Bulgaria, Croatia, France, Greece,Turkey and Tunisia are currently unknown. Declines are suspected in Croatia (for at least one colony [I. Budinski in litt. 2011]) and Greece (based on long-term trends [J. Fric in litt. 2011]) however the Greek population was reported as stable according to the European Red List of Birds (BirdLife International 2015).
It has been reported that the species is declining in Italy by 10-50% over 13 years (N. Baccetti in litt. 2011), in France by 6% per year (Oppel et al. 2011) and in Malta by 0-15% over nine years (Borg and Sultana 2002, Raine et al. 2009, Sultana et al. 2011). In total, these three countries represent around three-quarters of the known global population. By combining data for these three countries it is predicted that, if the species continues to decline at the current reported rate, the global breeding population will decrease by more than 30% in the next 54 years, i.e. three generations (Derhé 2012). These declines are retained despite increases reported for Italy and Malta in the 2015 European Red List of Birds (BirdLife International 2015). The reported increases may be either dependent on the trend at one colony or may be a result of better knowledge rather than real increases. Consultation with experts in the relevant countries suggests that overall the negative trends should be retained for the current assessment. However should new information suggest that these populations are experiencing genuine increases the global trend direction should be amended.
This species is endemic to the Mediterranean basin, but its precise distribution is not well known and numbers are disputed (Bourgeois and Vidal 2008). The main breeding colonies are concentrated in the central and eastern basin of the Mediterranean, from Sardinia through the central Mediterranean, the Adriatic and the Aegean (Borg et al. 2010). The species is known to breed in France (627-1044, Cadiou 2015), Italy (9,000-20,000 pairs, 12,791-19,774 according to BirdLife International 2015), Malta (1,370-2,000 pairs, according to Barbara et al. 2015), Algeria (8-10 pairs), Tunisia (176-200 pairs), Croatia (300-500 pairs, 300-400 pairs according to BirdLife International 2015), Albania (1-10 pairs), Greece (4,000-7,000 pairs) and Bulgaria (0-10 pairs) giving a global estimate of 15,300-30,500 pairs according to Derhé (2012) and 19,400-31,200 pairs according to BirdLife International (2015). Breeding is assumed in Turkey on offshore islands or mainland cliffs in the Aegean and Mediterranean, but so far no colonies have been identified and more surveys are needed (D. Sahin in litt. 2015).
A small population may also breed on the eastern Balearic Islands in Spain, although the existence of the species here is somewhat controversial, given the taxonomic uncertainty of the birds breeding in Menorca (Arcos 2011, Curé et al. 2010, Genovart et al. 2012). During the non-breeding season some birds migrate north-eastwards towards the Black Sea, although some birds may remain close to breeding colonies or disperse around the Mediterranean (Militao et al. 2013, Péron et al. 2013, Raine et al. 2013, Carboneras et al. 2014). More than 90,000 individuals were recorded passing through the Bosphorous in early February 2014 (D. Sahin in litt. 2015), at a time when most breeders in France and Malta have usually returned to their colonies.
Population trends in Albania, Algeria, Bulgaria, Greece, Tunisia, Croatia, France and Turkey are currently unknown (BirdLife International 2015). The population has been estimated to be declining rapidly in Italy (N. Baccetti in litt. 2011), however trends reported for the European Red List of Birds suggest the population may be increasing (BirdLife International 2015). The reported increase in the Italian population is highly dependent on the trend of the most important breeding site, Tavolara, where numbers are thought to be steadily increasing (E. Dupre, L. Serra in litt. 2015). However it is not clear whether reported increases are a result of changes in methodologies for monitoring population trends (N. Baccetti in litt. 2015). Declines have previously been reported for France (Bonnaud et al. 2009, 2012) and Malta (Borg and Sultana 2002, Raine et al. 2009, Sultana et al. 2011; Oppel et al. 2011), although the Maltese population was reported as increasing in the 2015 European Red List of Birds (BirdLife International 2015) but this may be as a result of better knowledge of the species rather than a genuine increase (B. Metzger in litt. 2015). Nine colonies have gone extinct over the last 60 years (Bourgeois and Vidal 2008) and since 2009, one breeding colony off Sardinia (San Pietro Island) has been reported as absent, possibly extinct (N. Baccetti in litt. 2011), and no breeding has been recorded anymore in Corsica (Cadiou 2015). Most worryingly, breeding success at many colonies appears to be extremely low and adult survival probabilities across the western Mediterranean have been reported as too low to maintain stable populations (Oppel et al. 2011).
It breeds in burrows, rocky cavities or big caves on rocky coastal and offshore islets, and on steep, inaccessible cliffs on the mainland. In the non-breeding season it disperses widely within the Mediterranean and Black Seas, often congregating in large flocks (Snow and Perrins 1998).
The most serious threat to the species is mortality from incidental capture in commercial and artisanal fisheries, followed by predation by invasive predators (predominantly Black Rats Rattus rattus and to a lesser extent, Feral Cats Felis catus). A study in France and Malta (Oppel et al. 2011) implicated fishing bycatch as a critical cause of mortality for the species, since the majority of the adult mortality of birds breeding in Malta occurred during the non-breeding season, and adult survival in France remained low after feral cat removal. This pattern is consistent with the presumed cause of low adult survival probabilities in the Balearic Shearwater Puffinus mauretanicus (Oro et al. 2004, Tavecchia et al. 2008, Genovart et al. 2016). Long-liners in particular affect the species (Arcos et al. 2008, Louzao et al. 2011, Militao et al. 2013), often on an irregular basis, but impacting fairly large numbers at a time. Since Procellariiforms are generally long-lived, their populations are highly sensitive to changes in adult survival. The increased adult mortality induced by bycatch is therefore a significant danger to them and a highly important threat (Lebreton 2000). Breeding success may also be affected by reduced abundance of anchovies and sprats due to competition from fisheries (Bourgeois and Vidal 2008). Direct persecution (bird shooting) remains pervasive in Malta, and both legal and illegal shooting activities have affected many local bird populations for decades (Magnin 1986, Raine 2007, Raine and Temuge 2009). Illegal shooting was likely responsible for the extremely low survival rates between 1969 and 1994 (Oppel et al. 2011).
The species has been shown to suffer substantial predation pressure by introduced mammalian predators on breeding grounds (Bourgeois et al. 2008, Bonnaud et al. 2009) with observed population declines in Italy being attributed to alien predators, predominantly rats (Capizzi et al. 2010, Sultana and Borg 2006). Rats are thought to limit reproductive success by depredating chicks and eggs, as evinced from nest traces (Martin et al. 2000). The Italian population of Yelkouan Shearwaters accounts for more than half of the global population and black rats are present on about 85% of the Italian islands, and on virtually all of those larger than 10 ha (Baccetti et al. 2009). On the Tavolara archipelago, Italy, the colony size has been much reduced in the last 30 years and vast sectors of the islands have been deserted; breeding success was assessed for the first time in 2006 and it was found to be zero in several colonies, attributed to rat predation (J. J. Borg in litt. 2006). However, Martin et al. (2000) detected no significant effect of rats on the distribution of Mediterranean Shearwaters, highlighting that rats were introduced to the Mediterranean islands more than 2000 years ago and the communities have had time to reach an equilibrium. They also showed that larger bird species, on larger islands appear to be more resistant and are able to maintain healthy population sizes in the presence of rats. Local extinctions by rats seem to have been concentrated on the smaller islands. Feral cats are another major threat. On the Hyères islands, cats have been identified as the primary predator of the species. Shearwater remains were found in up to 6% of cat scats, representing hundreds of adults killed each year, especially during the pre-breeding period (Bourgeois and Vidal 2008). The population on Port-Cros increased following feral cat eradication, implying that cat eradication may have led to higher recruitment in addition to a modest increase in adult survival (Bonnaud et al. 2012). The high level of cat predation on Levant Island in the Hyères islands could result in the extinction of the colony within four decades (Bonnaud et al. 2012).
Increasing tourism and coastal urbanization in the Mediterranean create sound and light pollution at colonies and causes disturbance and damage to fragile breeding habitats (Bourgeois and Vidal 2008, Oppel et al. 2011). The gregarious behaviour of this species makes it particularly vulnerable to oil spills and the intense maritime traffic in the Mediterranean and Bosporus increases the risk of spillage events. Light pollution at sea from bunkering areas, oil platforms and other at-sea structures may be an important threat for some colonies. Less prominent threats include collisions with off-shore wind farms (Raine et al. 2010), competition with native Scopoli’s Shearwaters Calonectris diomedea for nest sites (Bourgeois et al. 2015), pollution and contaminants including plastic (R. Crnkovic in litt. 2012, Codina-García et al. 2013), PCB (Bourgeois et al. 2011) and other organic contaminants. Two out of four eggs analysed on the Hyères islands exhibited PCB levels of concern and contamination could have caused breeding failure in these cases. Despite small sample sizes, Bourgeois et al.’s (2011) findings implied a high variability of contamination levels. It has also been suggested that the location of breeding sites along rocky coastlines and cavities in unstable substrates make the species vulnerable to changes in rainfall or storm surge intensity under climate change, but this potential threat is currently not supported empirically (Bourgeois et al. 2015).
Conservation and Research Actions Underway
EU Birds Directive Annex I; Annex II of the Bern Convention. An EU Life/BirdLife Malta project aimed at conserving a colony of c. 500 pairs at Rdum tal-Madonna, Malta, was completed in 2010. Malta declared in 2016 four marine protected areas (SPA) for Yelkouan shearwater. A third EU Life/BirdLife Malta project to assess all Yelkouan Shearwater colonies across the Maltese islands, identify and map threats, and apply conservation measures related with predator control, reduction of light pollution and disturbance to colonies was initiated in 2015. A rat eradication on Montecristo Island, Italy was completed in 2012 and has increased the breeding success of Yelkouan Shearwaters. A rat eradication programme was carried out on the islands of Zembretta and Zembrettina in Tunisia in 2009, resulting in an increase in the breeding population of Yelkouan Shearwater (Bourgeois et al. 2013). Two EU Life projects were completed in 2007 and initiated management and conservation actions on Hyères and Marseille islands that are still underway (rat and cat control, habitat management, artificial burrow installation). Artificial burrows were proved to be efficient in providing more stable breeding habitat, increasing breeding population size and allowing breeding success (Bourgeois et al. 2015). There is a species action plan (SAP) being prepared for this species by the French partner of Birdlife (La Ligue pour la Protection des Oiseaux), in collaboration with the Yelkouan Shearwater working group, and within the framework of the LIFE EuroSAP.
Conservation and Research Actions Proposed
Determine whether the species breeds in Turkey. Search for colonies at sites in Greece and Tunisia. Carry out population censuses at breeding colonies for which there is currently little reliable, up-to-date population size data, particularly those in Sardinia, Sicily and Greece. Continue breeding and non-breeding period counts at the Bosphorus and conduct breeding and non-breeding counts at other bottleneck sites. Research ecological requirements and carry out extensive demographic monitoring. Research the impact of introduced predators across breeding range. Research impact of predator control/ eradication programmes on annual survival and breeding success at different sites. As a precaution, control or if possible eradicate feral cats and rats at breeding colonies, according to a priority analysis and at sites with evidence of predation. Quantify extent of mortality from accidental bycatch. Encourage policymakers to implement and enforce measures that reduce accidental bycatch of Yelkouan Shearwaters and other seabirds in commercial fishing operations in the Mediterranean and Black seas. Propose the species for listing on Annex I of ACAP to address seabird bycatch (C. Carboneras in litt. 2015). Identify and implement measures to reduce/mitigate the effects of light pollution on the species (e.g. Raine et al. 2007).
36 cm. Medium-sized shearwater with blackish-brown upperparts contrasting sharply with almost entirely white underparts and underwings. Underwings only dark on tips, tailing edge and diagonal band across secondary coverts. Some brown on flanks, axillaries, undertail and underwing coverts. Feet are proportionally larger and extend slightly beyond tail, thus appearing longer-tailed at long range. Similar spp. Similar to P. puffinus but with browner upperparts, deeper-chested appearance, somewhat larger more attunuated body and longer wings. Flight and jizz more similar to P. mauretanicus which darkest individuals may closely resemble. Voice: Similar to P. puffinus; a raucous cacophony of cackles and howls but more drawling and with drawn-out falsetto notes.
Text account compilers
Miller, E., Moreno, R., Newton, P., Pople, R., Symes, A., Butchart, S., Calvert, R., Derhé, M., Ashpole, J, Ekstrom, J., Fjagesund, T., Harding, M., Martin, R.
Barbara, N., Budinski, I., Baccetti, N., Raine, A., Arcos, J.M., Crnkovic, R., Bourgeois, K., Petkov, N., Borg, J., Yésou, P., Perlman, Y., Raine, H., Oppel, S., Tavares, J., Militão, T., Dupre, E., Fric, J., Sultana, J., Şahin, D., Bourne, W.R.P., Zenatello, M., Ramírez, I., Metzger, B., Carboneras, C., McMinn, M., Corso, A., Serra, L., Sposimo, P.
BirdLife International (2020) Species factsheet: Puffinus yelkouan. Downloaded from http://www.birdlife.org on 23/10/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 23/10/2020.