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Résumé :
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This study presents the results collected from 2006 to 2008 on the namnetum subspecies of Bluethroat breeding in the marshland "Grande Briere - Marais de Donges" and "Brivet", both Natura 2000 sites in western France. The moderately dense to nearly dense reedbeds showing a height between 1 and 1.70 m were preferably selected by males. At the edge of marshland, males mostly select reedbed habita, in the centre of marshland where reedbeds are omnipresent males select more open areas with numerous small willows used as singing posts by the males. Males select singing posts 40 to 120cm above the overall vegetation height. Breeding success assessed in the Briere marshland is not significantly different from that found in the Guerande saltmarshes, the predation rate of nestlings are however higher in the former. But this result obtained on the particular site of the reserve where anthropic disturbance is high are probably overestimated and should not reflect the predation rate in the centre of marshland. The Bluethroat population is estimated to amount 3,500-4,400 males in the Brivet marshland (8,000 ha) thus representing 50% of the total population occurring at the French Atlantic coast. These figures are clearly higher than those obtained from previous estimates, showing the importance of the Briere marshland for the conservation of this particular subspecies and inciting to a better management of this site.
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