Justification This species has a tiny breeding range and a small population which is undergoing an extremely rapid population decline owing to a number of threats, in particular predation at breeding colonies by introduced mammals and at-sea mortality as a result of interactions with commercial fisheries. Population models predict an extremely rapid decline over three generations (54 years), qualifying the species as Critically Endangered.

Family/Sub-family Procellariidae

Species name author Lowe, 1921

Taxonomic source(s) AERC TAC (2003), Brooke (2004)

Taxonomic note Puffinus yelkouan (Sibley and Monroe 1990, 1993) has been split into P. yelkouan and P. mauretanicus following Brooke (2004).

Identification 33 cm. Medium-sized, rather dark shearwater. Upperparts dark brown contrasting slightly with the dirty, variably marked brown-whitish underparts. Most individuals show dusky undertail coverts and armpits. Similar spp. Easily told from Manx Shearwater P. puffinus by lack of strong contrast between upperparts and underparts. Dark individuals could be mistaken for Sooty Shearwater P. griseus but always show a white belly patch and lack the scythe-like wings and heavier flight of that species.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

6,000 - 10,000

decreasing

4,830,000 km²

Yes

Range & population Puffinus mauretanicus breeds in the Balearic Islands, Spain. In 2005, the most complete survey to date estimated 2,000-2,400 breeding pairs at 24 different sites, with the islands of Mallorca having 350-550 pairs; Cabrera 50-100 pairs; Menorca 100-175 pairs; Ibiza 200-300 pairs and Formentera <1,000 pairs¹². The world population was until recently believed to number 8,000-10,000 individuals^7,11, however recent winter at-sea surveys and counts from Gibraltar of post-breeding birds leaving the Mediterranean suggest the total population may in fact lie within in the range 20,000-30,000 individuals¹⁵. Reasons for the discrepancy between breeding and non-breeding population estimates are unclear, but it is most likely that this species has a particularly large floating population of immatures and non-breeders. On Cabrera Island, 60% of the colonies have disappeared in the last few decades, while a recent survey of Formentera (where c.50% of the world population breeds) did not record any breeding in all 30 suitable caves visited in a single cliff⁴. Population viability analysis has shown that in the presence of environmental and demographic stochasticities, mean extinction time for the world population was estimated at 40.4 years, and mean growth rate showed a 7.4% decrease each year⁴. In winter, it occurs in the Balearic Sea and off the north-east Spanish coast with most of the population traditionally concentrated between Valencia and Catalonia from November to February. Some birds migrate north in summer to seas off the British Isles and the south of the Scandinavian Peninsula¹. Numbers recorded in the traditional post-breeding quarters have declined since the mid-1990, with a corresponding increase in numbers along the coasts of northern France and south-west U.K^7,16.

Ecology: It breeds on cliffs and small islets, is very philopatric and lays only one egg. Adult birds do not commence breeding until their third year⁷. Breeding takes place between February and June. When raising young, adult birds form concentrations on the east coast of Spain¹, where they mostly inhabit the productive continental shelf and associated fronts where high prey concentrations occur around the Ebro Delta⁶. Most birds leave the Mediterranean for a post-breeding moult in the Bay of Biscay, although some remain in the Alboran Sea¹.

Threats This is a long-lived species and therefore immediate threats affect adult mortality rates. Adult survival is the main conservation concern, as this is unusually low for a Procellariiform⁴. Threats include predation by introduced cats Felis domestica, genets Geneta geneta and rats Rattus rattus and R. norvegicus^1,13,14. Presence of rabbits at some colonies where they compete for nest sites or degrade habitat may be a problem¹³. Kleptoparasitism by Yellow-legged Gull Larus michahellis is a problem at some colonies¹³. Long-line fishing appears to be a more significant threat than previously thought, with birds becoming hooked and then drowned. The species's gregarious behaviour and its close association with fishing boats means that occasional "mass mortality" occurs when long-line boats fish close to flocks. Such an event probably caused the death of c.50 birds near Tarragona in 1999-2000¹. Fish waste from trawl fishing has become a very important source of food during the reproductive period, as other sources of food, e.g small pelagic fish populations, have declined^{1, 10}. A reduction in the amount of this waste that is disposed of at sea, along with a ban on trawl fishing during two months in spring, could be a serious threat to the species and reduce its reproductive success¹. The National Hydrological Plan (Spain) will reduce the amount of nutrients discharged at the Ebro delta and this will further reduce fish stocks in this key feeding zone for Puffinus mauretanicus¹. Available habitat for breeding is decreasing through encroachment by mammalian predators and urbanisation of the coastal zone. This is concerning as the species apparently has greater difficulty in recolonising suitable habitat than other shearwaters¹. Pollution is a possible threat, e.g. from hydrocarbons and high mercury levels¹. The mercury problem might be accentuated as the sea area close to the Ebro delta has higher than normal mercury levels¹. The potential threat of oil pollution should not be ignored. There is limited harvesting of adult birds on Formentera, which may have had a very negative effect over recent decades¹. The gradual northward movement of the non-breeding population may be affecting adult survival, and this shift may be due to global warming or alterations in fish distributions as a result of fisheries activities^7,9. The recent demographic decline has not yet decreased the species's genetic variability, and connectivity found among colonies at least does not exacerbate the species's extinction risk.¹⁰

Conservation measures underway In 2000, the Balearic government designated three new Special Protection Areas such that all the Important Bird Areas for nesting Puffinus mauretanicus are now protected¹. Rats have successfully been eradicated (5-years free) from Estell Xapat, Esclatasang, Redonda and Imperial (all Cabrera), and are under control on Dragonera, Conills and Malgrats. Other target islands include Eivissa and Espalmador¹³. Funds have been made available for the removal and control of mammalian predators from various colonies on Mallorca and Formentera¹. A number of actions are currently being implemented through species guardians SEO and SPEA as part of BirdLife's Preventing Extinctions programme. Research is underway on mortality in longline fisheries: SPEA has produced a questionnaire for fishermen and started to carry out individual interviews with fishermen at eight fish ports, and a bycatch report assessment will be produced in 2009. 1,000 copies of a best-practice guide for fishermen, with information on bycatch and seabirds, were produced by SPEA in a calendar format for December 2008-March 2010 for fishermen in Portugal. Action Plans for the species have been published at local, national or international level in 1991, 1999, 2004, and 2005¹⁴. A LIFE project for the species ran from 1991-2001¹⁴, and Spain and Portugal have a joint LIFE project running from 2004-2008 aimed at identifying marine IBAs, including for this species¹⁵. The first inventory of marine Important Bird Areas (IBAs) in Portugal was published in 2008, identifying important areas for Balearic Shearwater. The Spanish marine IBA inventory project is due to end in 2009 with the publication of a book of marine IBAs in Spain. A new continuing LIFE+ project will start in 2009 with the aim of integrating the marine IBAs in the Natura 2000 network and developing the appropriate management plans for the Special Protected Areas, and the results of the marine IBA project will be presented to regional governments. Work is underway to identify and delineate breeding and non-breeding foraging and congregatory areas, as well as migratory routes, for designation as SPAs in several European countries^8,9,11. Coordinated efforts to estimate the global population size are underway, through updated information at the breeding colonies and censuses at sea. Biannual surveys have taken place off the Portuguese coast since 2005, and a network of observers carries out simultaneous counts of birds off the Catalunyan coast. Aerial and oceanographic surveys have been carried out, revealing hotspots for the species along the continental shelf.

Conservation measures proposed Control and eradicate predators in breeding colonies identified to be at risk. Evaluate eradication of rabbits. Thoroughly study the problem of by-catch by long-line fishing and develop awareness campaigns directed at the fishing industry, in order to mitigate this threat. Ensure effective protection for nesting sites and monitor management plans. Raise awareness and stop human exploitation. Study small pelagic fish populations in the western Mediterranean and in the Vizcaya gulf to assess extent of over exploitation and how this affects Balearic Shearwaters. Ensure that bans on trawl fishing are coordinated to avoid the total absence of fishing waste. Assess the impact of pollutants and heavy metals on this species. Develop a rapid response plan for a potential oil spill close to main feeding and breeding areas. Improve understanding of at-sea distribution, including during the non-breeding season.

References Aguilar (1999). 1. J. Arcos and D. Oro in litt. (2002). 2. Gutierrez (2003). 3. Madrono et al. (in press). 4. Oro et al. (2004). 5. Igual et al. (2004). 6. Louzao et al. (2004). 7. Wynn and Yésou (2007). 8. Mourino et al. (2003). 9. Ysou (2003) 10. Genovart et al. (2007). 11. Arsuaga (2006). 14. Jones et al. (2008). 15. J. M. Arcos in litt. (2008). 16. Wynn et al. (2007).

Further web sources of information

Detailed species account from Birds in Europe: population estimates, trends and conservation status (BirdLife International 2004)

European Union Species Action Plan

Species Guardian Action Update November 2008

Text account compilers Phil Benstead (BirdLife International), Jeremy Bird (BirdLife International), Matt Harding (BirdLife International), Ben Lascelles (BirdLife International), Andrew O'Brien (BirdLife International), Nic Peet (BirdLife International), Andy Symes (BirdLife International)

Contributors José Manuel Arcos (SEO/BirdLife), Miguel McMinn, Daniel Oro (Institut Mediterrani d'Estudis Avançats), Richard Porter (BirdLife International), Kate Tanner (Royal Society for the Protection of Birds)

IUCN Red List evaluators Jeremy Bird (BirdLife International), Stuart Butchart (BirdLife International), Andy Symes (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Puffinus mauretanicus. Downloaded from http://www.birdlife.org on 10/2/2010

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

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