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Article Dans Une Revue Ibis Année : 2021

The demography of an increasing insular Eurasian Scops Owl ( Otus scops ) population in western France

Résumé

Rapid population declines of many long-distance Afro-Palaearctic migratory bird species are ongoing across Europe but the demographic drivers are often poorly understood, thereby limiting the development of appropriate conservation actions. Using long-term population monitoring (39 years), capture–mark – recapture data and a matrix m odel, we estimated demographic parameters and the effect of climate variables on adult survival, and modelled the dynamics of an increasing population of Eurasian Scops Owls Otus scops in a landscape with agric ultural abandonment in western Fra nce. The observed mean annual population growth rate was 1.055 (from 68 to 523 territorial males between 1981 and 2019). Over the study period, clutch size and hatching success were stable, but edging success and breeding success showed slight negative trends, probably due to density-dependence. Survival varied with age , with an increase during early life and evidence for rapid senescence from 4 years old. Adult survival remained stable and was positively linked to the amount of autumn rainfall in the Sahel and to the winter North Atlantic Oscillation. Survival of younger age-classes made the largest contribution to the variance of the population growth rate, followed by clutch size, edging success and survival of older birds. Such a long-term population increase in a landscape where intensive agriculture has decreased by 64.6% sheds some new light on the causes of the decline of European Scops Owl and other Afro-Palaearctic bird populations. We infer some of the possible causes of this large-scale decline, in particular food shortage, and discuss conservation measure s that could be applicable to reverse this trend.
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Dates et versions

hal-03343637 , version 1 (14-09-2021)

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Christophe Barbraud, Christian Bavoux, Guy Burneleau. The demography of an increasing insular Eurasian Scops Owl ( Otus scops ) population in western France. Ibis, 2021, ⟨10.1111/ibi.12995⟩. ⟨hal-03343637⟩
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