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Boileau N.,Les Marais | Delaporte P.,Ligue pour la Protection des Oiseaux LPO
Alauda | Year: 2012

This behaviour was observed during three winters in mudflats of the Marennes-Oléron bay (Western France). Kleptorasitism attempts (n = 44) occurred in 5% of captured preys (n = 878) and involved gulls (65%; Chroicocephalus ridibundus, Larus canus, Laws argentatus) but also Curlew (35%). Successful attempts were higher in gulls (62%) compared to curlews (26%). Worms were the major prey type stolen with handling time significantly higher in those prey types. No differences were observed in attack durations and vigilance time of attacked birds between curlews and gulls and kleptoparasitism rates did not differ among six different mudflats of the bay. Source

Bocher P.,CNRS Coastal and Marine Environment Laboratory | Quaintenne G.,CNRS Coastal and Marine Environment Laboratory | Delaporte P.,Reserve Naturelle Nationale de Moeze Oleron | Goulevant C.,Reserve Naturelle Nationale des Marais dYves | And 2 more authors.
Wader Study Group Bulletin | Year: 2012

The two subspecies of the Red Knot Calidris canutus that occur in Europe during northward and southward migration, islandica and canutus, are only observed simultaneously at a few sites such as the Wadden Sea. Mostly islandica winters on estuarine bays in NW Europe, while canutus go to wintering grounds in W or S Africa. The coasts of France have been described as the main southern limit of the winter distribution of islandica and as providing stopover sites for canutus migrating between the W African coast and breeding grounds in Siberia. Nevertheless, the role and the importance of French sites remain unclear for both subspecies, especially during southward migration. This study updates information on the numbers and the distribution of Red Knots staging or wintering along the coasts of France using International Waterbird Census (IWC) data (counts carried out in Jan, 1976-2010, organised by Wetlands International) and synchronized monthly counts carried out in France's National Nature Reserves during 2000-2010. In recent years, France has supported around 9% (c.35,000 individuals) of the estimated population of islandica in mid-winter. Ninety percent of these birds are concentrated in just six bays, two along the Channel coast and four along coasts of Vendee and Charente-maritime. As intertidal areas are limited along the Mediterranean shore, it does not support Red Knots in winter. Numbers of islandica peak in mid-winter, but significant passage of canutus occurs in May on the central Atlantic coast. Patterns of autumn migration remain unclear and information on occurrence of both subspecies is lacking. Long term trends in site use differ from place to place; this is probably an indication that they are used by birds of different origin and age. Source

Lucia M.,CNRS Coastal and Marine Environment Laboratory | Bocher P.,CNRS Coastal and Marine Environment Laboratory | Chambosse M.,CNRS Coastal and Marine Environment Laboratory | Delaporte P.,Ligue pour la Protection des Oiseaux LPO | Bustamante P.,CNRS Coastal and Marine Environment Laboratory
Journal of Sea Research | Year: 2014

This study investigated the link between trace element concentrations and respective diets of two shorebird species present in the Pertuis Charentais, Atlantic coast of France: the Dunlin (Calidris alpina) and Redshank (Tringa totanus). Trace element concentrations (Ag, As, Cd, Co, Cr, Cu, Fe, Hg, Mn, Ni, Pb, Se, Zn) were investigated in the liver, kidney, muscle and feathers of 28 dunlins and 15 redshanks accidentally dead during catches by mist net. Analyses of carbon and nitrogen stable isotope ratios were carried out in liver, muscle and feathers to determine whether differences in diet explained the variations in elemental levels. These results were compared to previous data obtained on two other shorebird species present on the same sites: the Black-tailed Godwit (Limosa limosa) and the Red Knot (Calidris canutus). This study demonstrated that shorebirds of the Pertuis Charentais were characterized by differential trace element bioaccumulation. Arsenic and Se concentrations in internal tissues were elevated in red knots and dunlins, whereas redshanks displayed higher Cd concentrations. These trace element bioaccumulation discrepancies could mainly come from divergences of trophic habits between shorebirds. Species with the highest trophic position displayed the highest Hg concentrations in the liver, muscle and feathers demonstrating therefore the biomagnification potential of this metal, as opposed to Cd and Pb. The same trend was observed in muscle and feathers for Se and only in feathers for As. These data highlighted the need to study several tissues to obtain a full comprehension of trace element exposure and pathways especially for long-distance migrating species using various habitats and sites. © 2013 Elsevier B.V. Source

Bocher P.,CNRS Coastal and Marine Environment Laboratory | Robin F.,CNRS Coastal and Marine Environment Laboratory | Deceuninck B.,Ligue pour la Protection des Oiseaux LPO | Caillot E.,Observatory of Coastal Shorebirds
Acta Ornithologica | Year: 2013

Abstract. Species with known long-term changes in abundance and distribution enable exploring the role of newly accessible sites in population regulation. In Western Europe, the Black-tailed Godwit Limosa limosa islandica is one of the few wintering shorebirds with increasing populations. The French coasts comprise a major wintering site within its global wintering area, with several thousand individuals at some sites. Nevertheless, the role and importance of French sites in general distribution patterns of the species remain unclear, especially as its hunting was legal there until 2008. In contrast, recent increases in protected areas in France (from 4,000 ha in 1973 to 28,000 ha in 2005) offer new safe sites and suitable habitats for the species. In this study, we assessed the numbers and distribution of Black-tailed Godwits along the coasts of Western France. The main wintering sites in France are progressively occupied from August, reaching peak occupation in late autumn or early winter although few of the ten sites listed showed similar patterns of monthly variations in the distribution of Godwit numbers. France welcomes c. 28% of the total L. l. islandica population in mid-winter over the period 2003-2007. Numbers declined steadily from the base year (1977) until 1991, then progressively increased, reaching a maximum in 2010 (c. 27,000 individuals). The creation of Nature Reserves throughout the 1990s probably contributed to the increasing number of Godwits in France, with new accessible sites visited and occupied intensively during the period of population increase. The clearly contrasting phenologies between the British Isles and France suggest that most of the individuals first arrive in the United Kingdom after the breeding season, and then some of the birds move to southern sites in either France or Iberia, while very few birds fly directly to France from Iceland. Source

Robin J.-G.,Le Daviaud Lecomusee du Marais Vendeen | Dulac P.,Ligue pour la Protection des Oiseaux LPO Vendee | Gueret J.-P.,Ligue pour la Protection des Oiseaux LPO | Piersma T.,University of Groningen | Piersma T.,Netherlands Institute for Sea Research
Wader Study Group Bulletin | Year: 2012

In recent decades, the NW Europe population of the nominate subspecies of the Black-tailed Godwit, Limosa limosa limosa, has been in steep decline. As no changes in survival have been apparent so far, these declines are likely to have been caused by declines in recruitment, possibly due to decreasing quality and availability of breeding habitat. Most nominate Black-tailed Godwits breed in agricultural grasslands in the Netherlands and, to some extent, in Germany. Here we show that, in contrast to the general decreasing trend, numbers of breeding pairs have actually increased at the southernmost limit of their distribution in France, from 51 pairs in 1985 to 164 pairs in 2011. We review current knowledge of this godwit population as a basis for a demographic study. Source

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