Conference PaperPDF Available

Movements and ‘moving’ population estimates of Yelkouan Shearwater Puffinus yelkouan at Tavolara, Sardinia

Authors:
  • Area Marina Protetta Tavolara Punta Coda Cavallo

Abstract and Figures

An ongoing monitoring programme allowed the re-assessment of the population size of Yelkouan Shearwater Puffinus yelkouan breeding at Tavolara (Sardinia, Italy), the largest world colony of this species. Results point at 9,991-13,424 breeding pairs, obtained by afternoon counts from land of birds approaching the colony and confirmed by the census of ground plots. Feeding areas of breeding adults, investigated with GPS loggers, stretch for some hundred kilometres and are mostly located at coastal gulfs of N and W Sardinia and SW Corsica, between Oristano, Ajaccio and the Maddalena archipelago. Counts from land suggest that the Orosei Gulf, in E Sardinia, might also be used.
Content may be subject to copyright.
A preview of the PDF is not available
... nidificanti in Italia (Gaudard, 2018) e distribuite in una trentina di isole di piccole e medie dimensioni e su alcuni tratti rocciosi della costa sarda. La più importante colonia nota per la specie si trova sull'isola di Tavolara che da sola ospita oltre il 50% della popolazione globale (Zenatello et al. 2012). Essendo una specie longeva che raggiunge la maturità sessuale a 3-4 anni di età, ai riproduttori deve essere aggiunta una rilevante frazione di individui immaturi che contribuiscono alla consistenza complessiva della popolazione. ...
... nidificanti in Italia (Gaudard, 2018) e distribuite in una trentina di isole di piccole e medie dimensioni e su alcuni tratti rocciosi della costa sarda. La più importante colonia nota per la specie si trova sull'isola di Tavolara che da sola ospita oltre il 50% della popolazione globale (Zenatello et al. 2012). Essendo una specie longeva che raggiunge la maturità sessuale a 3-4 anni di età, ai riproduttori deve essere aggiunta una rilevante frazione di individui immaturi che contribuiscono alla consistenza complessiva della popolazione. ...
... For Yelkouan Shearwater, where a single Italian island accounts for more than half of the known global population (Zenatello et al. 2012), chicks fledge in most years only in a few rat-free caverns, that are hardly relevant in terms of population (less than 1%). Factors explaining Ruffino's paradox (cf. ...
Conference Paper
Full-text available
A review of all the eradication projects involving Rattus rattus that have been carried out since 1999 on 14 Italian islands is presented. Data on different aspects related to the problem of rats on these islands are discussed, ranging from impact and benefit quantification, eradication methods and outcomes, to social problems such as lack of public awareness. A model aimed at identifying priority islands where eradication should be carried out was developed according to available budgets, an exercise that is worth extending throughout the Mediterranean.
... For Yelkouan Shearwater, where a single Italian island accounts for more than half of the known global population (Zenatello et al. 2012), chicks fledge in most years only in a few rat-free caverns, that are hardly relevant in terms of population (less than 1%). Factors explaining Ruffino's paradox (cf. ...
... For Yelkouan Shearwater, where a single Italian island accounts for more than half of the known global population (Zenatello et al. 2012), chicks fledge in most years only in a few rat-free caverns, that are hardly relevant in terms of population (less than 1%). Factors explaining Ruffino's paradox (cf. ...
Book
Full-text available
CONSERVATION OF MARINE AND COASTAL BIRDS IN THE MEDITERRANEAN PROCEEDINGS OF THE UNEP-MAP - RAC/SPA SYMPOSIUM, HAMMAMET - TUNISIA - 20 TO 22 FEBRUARY 2015
... These areas overlap with the foraging grounds of Balearic shearwaters from Balearic Islands (Eivissa, Formentera, Mallorca and Menorca, [39], [88], [89]) and with those of Yelkouan shearwaters from Marseille and Hyè res islands (France, [40]). There are more colonies of Yelkouan shearwaters in the Western Mediterranean but present evidences suggest they do not forage in the NE coast of Spain [90]. doi:10.1371/journal.pone.0115650.g002 ...
Article
Full-text available
Correct species identification is a crucial issue in systematics with key implications for prioritising conservation effort. However, it can be particularly challenging in recently diverged species due to their strong similarity and relatedness. In such cases, species identification requires multiple and integrative approaches. In this study we used multiple criteria, namely plumage colouration, biometric measurements, geometric morphometrics, stable isotopes analysis (SIA) and genetics (mtDNA), to identify the species of 107 bycatch birds from two closely related seabird species, the Balearic (Puffinus mauretanicus) and Yelkouan (P. yelkouan) shearwaters. Biometric measurements, stable isotopes and genetic data produced two stable clusters of bycatch birds matching the two study species, as indicated by reference birds of known origin. Geometric morphometrics was excluded as a species identification criterion since the two clusters were not stable. The combination of plumage colouration, linear biometrics, stable isotope and genetic criteria was crucial to infer the species of 103 of the bycatch specimens. In the present study, particularly SIA emerged as a powerful criterion for species identification, but temporal stability of the isotopic values is critical for this purpose. Indeed, we found some variability in stable isotope values over the years within each species, but species differences explained most of the variance in the isotopic data. Yet this result pinpoints the importance of examining sources of variability in the isotopic data in a case-by-case basis prior to the cross-application of the SIA approach to other species. Our findings illustrate how the integration of several methodological approaches can help to correctly identify individuals from recently diverged species, as each criterion measures different biological phenomena and species divergence is not expressed simultaneously in all biological traits.
Article
Full-text available
We review and update available information on the population size and distribution of Cory's Shearwater, Calonectris diomedea, and Yelkouan Shearwater, Puffinus yelkouan, in Italy. More than 90% of the population of these species rely on 64 islands, but the former breeds on twice as many islands as the latter. Some cases of local extinction were recorded. The analysis of distributions, along with that of island featu-res and presence of rats, showed inter-specific differences. The Yelkouan Shearwater tends to occupy larger and more offshore islands than the other species does. It's the only one that shows a clear positive correlation between abundance and island size. Finally, it is not present in rat-free islands, with a single exception of no quantitative relevance. Available data on the breeding success of both species are presented; comple-te failures where rats occur were recorded. Operations of rat control or eradication are presented and their consequences on seabirds' breeding success commented.
Article
Full-text available
The endemic Mediterranean yelkouan shearwater Puffinus yelkouan, elevated to the rank of species in 2002, is poorly monitored and studied. Despite this lack of data and the susceptibility of closely related species to threats at breeding sites and foraging areas, the yelkouan shearwater is currently considered to be at low risk of extinction. This review, based on published documents, personal communications with scientists and our own observations, summarizes available data on range, population size and trends, and on threats to the species' existence. Breeding sites range from the Marseille islands (France) to Bulgarian islands in the Black Sea but many are not confirmed. The estimated global population is 11,355-54,524 pairs but most censuses are probably overestimates and the global population could be only a few thousand breeding pairs. There is evidence of a population decline and susceptibility to introduced mammals, particularly feral cats Felis catus and ship rats Rattus rattus, and to accidental bycatch in fishing gear. We highlight the lack of accurate and regular censuses of the species, and the alarming situation suggested by the little data available. We recommend that the yelkouan shearwater be categorized as Near Threatened on the IUCN Red List, encourage collaborative work to clarify its status, and make a plea for more data on the species’ demography and ecology, and for the evaluation of terrestrial and marine threats.
Article
Full-text available
Using combined miniature archival light and salt-water immersion loggers, we characterise the year-round individual at-sea movements of Europe's only critically endangered seabird, the Balearic shearwater Puffinus mauretanicus, for the first time. Focusing on the non-breeding period, we show that all of the 26 breeding birds tracked from their breeding site on Mallorca in the Mediterranean Sea successfully made a 2-4 month migration into the Atlantic Ocean, where they utilised well-defined core areas off Portuguese and French coasts. As well as identifying high-risk areas in the Atlantic, our results confirm that breeding birds spend most of the year concentrated around productive waters of the Iberian shelf in the western Mediterranean. Migration phenology appeared largely unrelated to the subsequent (distinctly synchronous) breeding attempt, suggesting that any carry-over effects were compensated for during a long pre-laying period spent over winter in the Mediterranean. Using the light and salt-water immersion data alone we were also able to characterise the pattern of pre-laying visits to the colony in considerable detail, demonstrating that breeding pairs appear to coordinate their over-day visits using a high frequency of night-time visits throughout the winter. Our study shows that geolocation technology is a valuable tool for assessing the spatial distribution of risks to this critically endangered species, and also provides a low-impact method for remotely observing the detailed behaviour of seabird species that may be sensitive to disturbance from traditional study methods.
Article
A data logger devised and manufactured by our research team in order to study the homing routes of carrier pigeons was subsequently modified to study the homing behaviour and foraging strategies of breeding marine birds. Recent versions of the data logger, equipped with a flight sensor and depth meter or saltwater switch, were used in a study of the foraging strategies of chick-rearing Balearic shearwaters (Puffinus mauretanicus) in the framework of the project LIFE-Puffinus financed by the Balearic Government and the EU. Due to low recapture rates (only 3 out of 6 tagged birds were recovered), only preliminary data from a small sample are available. Data loggers have recorded data on the pattern of nest attendance (including departure time to foraging trips and return time) and the diurnal pattern of flight and dive activity (including depth and duration of dives). Despite the small sample size, the results show that our data loggers can successfully be applied to the study of the breeding biology and foraging ecology-including the diving pattern-of Balearic shearwaters and similar species.
Chapter
With a surface of 24,090 km2, Sardinia is the second largest island in the Mediterranean where it is centrally situated. The Sardinian coastline extends over nearly 1,900 km, whereof 1,385 km (73%) belong to the main island while the remaining 512 km (27%) belong to the various smaller islands (275 km2), all situated on a common continental shelf and prevalently off the four corners of Sardinia. About 75% of the coastline is rocky, consisting of cliffs and rocks falling into the sea. Particularly sheer stretches can be found in the Gulf of Orosei, around Capo Caccia and Capo Teulada and on the Island of Tavolara. They are all of calcareous formation, abounding in caves, cavities, rock ledges and terraces.
Article
We describe, for the first time, nest-cavities selected by the Mediterranean endemic yelkouan shearwater Puffinus yelkouan on French islands, comparing it with the sympatric Cory's shearwater Calonectris diomedea. By monitoring 179 suitable cavities during four years, we show that yelkouan shearwaters select deeper cavities and with more winding tunnels than those selected by Cory's shearwaters or unoccupied cavities. Logistic regression modelling indicates that cavities with nest-like characteristics are not limited. We show that breeding success is enhanced in deeper cavities, with winding tunnels and higher block covers. We do not find any apparent competition between the two shearwater species.
Article
We describe and test the influence of several environmental and biological factors on the presence and activity patterns of the Mediterranean endemic yelkouan shearwater Puffinus yelkouan at colonies. Bird arrival at breeding sites is highly correlated with nautical dusk for moonless or slightly moonlit nightfalls and correlated with moonset when the moon is visible. Breeding cycle and wind speed affect both the arrival times and presence at colonies. Bird activity also varies throughout the night and sex ratio on colonies throughout the breeding cycle in relation to breeding duties. Breeder and non-breeder behaviour particularly differs in the time spent on the ground outside burrows, without protection. Finally, factors other than moonlight can be essential in determining the presence and behaviour of petrels and shearwaters at breeding sites, and we need to determine how differences in behaviour at colonies could be related to differential predation risk.
Sviluppo di un sistema nazionale delle ZPS sulla base della rete IBA (Important Bird Areas) On-line report, 730 pp. www.lipu.it/pdf/relazione_iba
  • A Brunner
  • C Celada
  • P Rossi
  • M Gustin
  • T Guilford
  • R Wynn
  • M Mcminn
Brunner, A., Celada, C., Rossi, P. & Gustin, M. 2002. Sviluppo di un sistema nazionale delle ZPS sulla base della rete IBA (Important Bird Areas). On-line report, 730 pp. www.lipu.it/pdf/relazione_iba.zip Guilford, T., Wynn, R., McMinn, M., Rodriguez, A., Fayet, A., Lou, M., Jones, A. & Meier, R. 2012.