La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Survival explains sex ratio in an introduced Mandarin Duck Aix galericulata population (2015)
Auteurs :	Jochen Bellebaum, Auteur ; Wolfgang Maedlow, Auteur
Type de document :	Article
Dans :	Ardea (103(2) Winter, 2015)
Article en page(s) :	183-187
Résumé :	Adult sex ratio in ducks is male-biased, probably due to higher mortality of incubating females. In an introduced population of Mandarin Ducks Aix galericulata in Berlin and Potsdam, adult sex ratio (proportion of males) was 0.65 (95% confidence interval 0.64-0.67). Annual apparent survival of 163 colour-ringed birds during 2003-2012 was 0.65 (0.55-0.76) for first year and 0.66 (0.60-0.72) for adult males, and 0.47 (0.25-0.69) for first year and 0.57 (0.48-0.66) for adult females. Female mortality but not male mortality peaked during the breeding season. A Leslie matrix model based on productivity and survival rates in the study population estimated an adult sex ratio of 0.64, or 0.67 when first-year birds were excluded. The similarity between observed adult sex ratio and model estimates based on survival suggests that the male-bias might be fully explained by sex differences in survival.

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