recensement national des colonies de gran ds cormorants Phalacrocorax carbo en France en 2018 et comparaison avec celui de 2015
Résumé
National census of Great Cormorant Phalacrocorax carbo colonies in France in 2012. This fourth national census showed 8666 +/- 51 breeding pairs of Great Cormorant in France in 2012 (7213 +/- 81 breeding pairs in 2009). The mean annual increasing rate was of 6.31%. 131-134 colonies (109-113 in 2009) were distributed over 42 departments (administrative counties in France). The coastal population restricted to 7 departments (Somme southwards to Morbihan) showed a small increase of 2.64% since 2009 and amounted 2045 breeding pairs in 27 colonies (1985 breeding pairs in 28 colonies in 2009 and 1976 in 31 colonies in 2006). The coastal population of Normandy still decreased (-11%; -122 nests in addition to -117 nests between 2006 and 2009). In Brittany however the breeding figures increased by 21% (+170 nests). The inland population existing since 1981 at Grand-Lieu (western France) levelled-off geographically in 2012 (occurrence in 40 departments in 2012 compared to 37 in 2009 and 29 in 2006) mainly in the northern part of France. The inland population increased by 26.64% amounting 6621 +/- 51 pairs in 104-107 colonies (5228 breeding pairs in 81-85 colonies in 2009, representing an mean annual increasing rate of 8.22% in breeding pairs against 5.38% between 2006 and 2009). The largest colonies which appeared in the years 1980-1990 seem to be stabilized since several years, excepted the Grand-Lieu colony which decreased by 50% since the peak reached in 2007 (it is however still the largest colony in France amounting 739 pairs). The Normandy region represents 22.9%of the national population, those of Pays de la Loire 22.1%, Brittany 11.8%, Nord 9.6%and Picardy 7%. The remaining inland populations were scattered over 60 small colonies which often survive under less favourable feeding conditions.