Sylvain Dromzée

The Royal Society for the Protection of Birds, Sandy, England, United Kingdom

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Publications (7)11.27 Total impact

  • Karen Bourgeois, Sylvain Dromzée, Eric Vidal
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    ABSTRACT: 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 whether 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.
    Acta Ornithologica 06/2014; 49:9-22. · 1.68 Impact Factor
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    ABSTRACT: Prions Pachyptila are abundant seabirds in the Southern Ocean that have been used to infer environmental change, but this relies on an understanding of their morphological diversity. Species limits among prions are largely defined by the size and structure of their bills. The broad-billed prion P. vittata, which breeds at temperate islands in the central South Atlantic Ocean and around New Zealand, is the largest species with adult bill widths averaging 21–22 mm. We report local differences in bill sizes on Gough Island, with typical adults breeding in some areas and narrower-billed birds in other areas (average bill width 18–19 mm, although at one site there was a second mode at bill widths of 16–17 mm). The narrow-billed birds have slightly shorter bills, heads and wings (averaging 1–2 % smaller than typical adult broad-billed prions), but the difference in bill width is much more marked (15 %). The small-billed birds differ from typical broad-billed prions in having blue colouration in the upper mandible and are similar in size to MacGillivray’s prion P. [salvini/vittata] macgillivrayi from Amsterdam and St Paul islands in the temperate Indian Ocean. The occurrence of two prion morphs on Gough Island raises intriguing questions about their ecology and systematics. Small-billed birds breed 3 months later than large-billed birds, suggesting that they are a separate species, not an example of bill polymorphism.
    Polar Biology 05/2014; 37(5):727-735. · 2.01 Impact Factor
  • Karen Bourgeois, Sylvain Dromzée
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    ABSTRACT: Biochemical analyses of feathers are increasingly used to study seabird at-sea distribution, movements, pollutant exposure and trophic level. However, such studies are intrinsically related to the knowledge of the target species moulting strategies. In this study, we analysed the moulting strategies of the Yelkouan Shearwater Puffinus yelkouan at three breeding sites, by scoring the moult of wing, tail and body feathers during the breeding season. While we observed virtually no bird growing its wing feathers, some Yelkouan Shearwaters started moulting their tail and body feathers during late incubation. Moult intensified during chick-rearing. We did not find any significant effect of sex, breeding status or year on moulting patterns. However, moulting strategies varied among individuals, as only a proportion of birds was actively moulting at the various breeding stages and moulting patterns varied among breeding sites. Based on our study, it is evident that factors determining moulting strategies in the Yelkouan Shearwater remain to be elucidated. This study underlines the need to carefully select the most convenient target feathers to ensure the correct development of studies based on the biochemical analysis of feathers as moulting strategies in seabirds can be rather variable.
    Journal of Ornithology 01/2014; 155(1):265-271. · 1.63 Impact Factor
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    ABSTRACT: 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.
    Biological Invasions 03/2013; 15(3):475-482. · 2.51 Impact Factor
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    Karen Bourgeois, John W. Wilson, Sylvain Dromzée
    Marine Ornithology 01/2013; 41:135-136.
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    ABSTRACT: We tested whether colony-site availability could allow for an increase in the unusually small breeding populations of yelkouan shearwater (Puffinus yelkouan) on the islands of the Port-Cros National Park (France) if feral cat eradication were undertaken. Comparisons between colony and noncolony sites indicated yelkouan shearwaters preferred deep-soiled and low-outcrop-covered coastal sites. A substrate cover, light avoidance, and sea proximity model suggested that 17.5% of unoccupied sites are suitable for colony establishment. The low proportion of suitable sites currently used by yelkouan shearwaters suggests that these colonies could be refuges and that feral cat eradication will probably lead to a breeding population increase.
    Journal of Wildlife Management 07/2008; 72(5):1188 - 1193. · 1.64 Impact Factor
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    ABSTRACT: 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.
    Comptes Rendus Biologies 01/2008; 331(1):88-97. · 1.80 Impact Factor

Publication Stats

15 Citations
11.27 Total Impact Points

Institutions

  • 2014
    • The Royal Society for the Protection of Birds
      Sandy, England, United Kingdom