A Dos dIles

La Chapelle-de-la-Tour, France

A Dos dIles

La Chapelle-de-la-Tour, France
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Bourgeois K.,University of Auckland | Bourgeois K.,CNRS Mediterranean Institute for Biodiversity and Ecology Marine and Continental | Dromzee S.,A Dos dIles | Vidal E.,University of New Caledonia
Acta Ornithologica | Year: 2014

Nest and mate choice is important in seabirds, influencing reproductive performance as both nest-site and partner quality varies. The Yelkouan Shearwater Puffinus yelkouan nests mainly in pre-existing cavities and to a lesser extent in cavities it excavates. We have monitored breeding colonies of the Yelkouan Shearwater on two islands of the Hyères archipelago, south-east of France, for nine years to analyse nest-cavity and mate selection, to evaluate nest-cavity and mate fidelity, and to investigate their relationships with reproductive performance. Yelkouan Shearwaters selected nest-cavities providing a high degree of concealment and protection. Reproductive performance and fidelity to cavity were highest in deep cavities with a winding tunnel and a steep slope around the entrance. Mating was assortative for bill and tarsus measurements. High rates of return to the same cavity (94.7%) and mate (95.5%) were recorded. Fidelity to nest-cavity was highest when breeding succeeded the previous year (fidelity rate: 97.3% in successful breeders vs. 87.8% in unsuccessful breeders) and was most likely to result in successful breeding the same year (breeding success: 67.5% in faithful breeders vs. 43.8% in movers). The rate of divorce was low (4.5%), did not differ between islands and was not associated with breeding performance. However, breeding success increased by 22.2 ± 9.9% after mate change following a divorce or the absence of a previous mate. Such high rates of nest-cavity and mate fidelity could indicate a good population status with breeding habitat, food resource and mates of good quality.

Bourgeois K.,University of Auckland | Bourgeois K.,CNRS Mediterranean Institute for Biodiversity and Ecology Marine and Continental | Dromzee S.,A dos dIles | Vidal E.,University of New Caledonia
Biological Conservation | Year: 2015

Seabirds are one of the most threatened animal taxa worldwide as they have to deal with threats both at sea and on their breeding grounds. One of these threats is the loss and deterioration of their nesting habitat. Here, we evaluated the long-term effectiveness of providing artificial burrows for the conservation of Yelkouan (Puffinus yelkouan) and Scopoli's (Calonectris diomedea) shearwaters on two islands of the Hyères archipelago (Mediterranean, France). We estimated and compared the longevity, occupancy of and breeding success in artificial burrows and natural cavities. We also analysed factors affecting these three parameters in artificial burrows to optimize their installation for the conservation of our study species. Although their efficacy depended on the species and the island considered, artificial burrows provided more stable and persistent breeding habitat (12-years persistence: 80% vs. 72%), allowed the recruitment of new breeders and good reproductive success (49-76%), and probably reduced inter-specific competition for nesting cavities, across the two islands. The characteristics of both artificial burrows and the areas where they were installed affected artificial burrow efficacy in terms of longevity and occupancy by shearwaters. Thus, artificial burrows were successful tools for the conservation of these two Mediterranean species of shearwaters, particularly when their design and installation were optimized by limiting the risk of their destruction and by selecting burrow and habitat characteristics that enhance their occupancy by the target species. The evaluation of such conservation measures should be performed for every species and site to help managers design and implement effective conservation plans. © 2015 Elsevier B.V.

Bourgeois K.,A dos diles | Ouni R.,Tunis el Manar University | Pascal M.,French National Institute for Agricultural Research | Dromzee S.,A dos diles | And 2 more authors.
Biological Invasions | Year: 2013

The ship rat (Rattus rattus) was introduced 1,500 years ago to the Zembra Archipelago (Tunisia) and was eradicated in October-November 2009 on two of its islands, Zembretta and Zembrettina. This eradication was performed 2 years after the discovery of a small colony of Yelkouan shearwaters (Puffinus yelkouan), a species recently up-listed to the vulnerable IUCN extinction risk category. For 2 years before and 3 years after rat eradication, the Zembretta Yelkouan shearwater breeding colony was checked yearly at the end of the breeding season. The number of recorded breeding pairs reaching 176 and 145, respectively, increases of 10. 4 and 8. 5-fold two and 3 years after rat eradication. This experiment shows that eradication of an ancient introduced ship rat population has dramatically improved the Zembretta Yelkouan shearwater breeding population very quickly. This result suggests that managing even long-introduced populations might well be fruitful. © 2013 Springer Science+Business Media Dordrecht.

Oppel S.,Royal Society for the Protection of Birds | Raine A.F.,BirdLife Malta | Borg J.J.,National Museum of Natural History | Raine H.,BirdLife Malta | And 4 more authors.
Biological Conservation | Year: 2011

Many seabird species are experiencing population declines, with key factors being high adult mortality caused by fishery by-catch and predation by introduced predators on nesting islands. In the Mediterranean, both of these pressures are intensive and widespread. We studied the adult survival of an endemic Mediterranean seabird, the Yelkouan shearwater (Puffinus yelkouan), between 1969-1994 and 2007-2010 in Malta and between 2004-2010 in France using mark-recapture methods. Mean annual survival probabilities for breeding adults were below 0.9 for all colonies and periods. Between 1969-1994, annual survival for adults of unknown breeding status was on average 0.74 (95% confidence interval: 0.69-0.80) in Malta, possibly as a result of various human disturbances (including illegal shooting), light pollution and fisheries by-catch. Over the period 2004-2010, we found strong support for variation in adult survival probabilities between breeders and non-breeders, and islands with and without introduced predators in France. Survival probabilities for non-breeders (0.95, 0.81-1.0) appeared to be higher than for breeders (0.82, 0.70-0.94), but were imprecise partly due to low recapture probabilities. In Malta, we found evidence for heterogeneity in survival probabilities between two unknown groups (probably breeders and non-breeders), and seasonal variation in survival probability. Birds were more likely to survive the period including the peak breeding season than an equally long period during which they roam widely at sea. Although annual adult survival probability was still low (0.85, 0.58-1.0), colony protection measures appear to have reduced mortality at nesting cliffs. A population model indicated that colonies in France and Malta would currently require continuous immigration of 5-12 pairs per year to maintain stable populations. Our estimates of adult survival probabilities over the past four decades are consistent with overall population declines. Threats to Yelkouan shearwaters require immediate management actions to avoid ongoing population declines in the western Mediterranean. © 2011 Elsevier Ltd.

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