Aves, p�le ornithologique de Natagora

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Aves, 55/1 | 2018 | 1-31

  The worrying trends in breeding bird populations of in Wallonia : 28 years of common bird monitoring
Antoine Derouaux & Jean-Yves Paquet

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Article summary

Every year since 1990 the population trends of the most common breeding birds in Wallonia (81 species) have been estimated using a standardized sampling procedure. Several dozens of volunteers make one or more sets of 15 fixed spots where birds are counted for 5 minutes. Each year, the observers repeat the observation following the same methodology. From these data, an annual abundance index has been calculated for each species and population trends are estimated. Over the last 28 years, most common species are declining in Wallonia. Only 26 % of them have shown an increase in numbers.On average across all species, bird populations have declined at a rate of 1 % per year for the last 28 years. In the last 10 years the average rate of decline has accelerated. The rate of decline is greatest in farmland birds, especially in the ground-nesting species. The rate of decline has been greater in migratoryspecies which cross the Sahara than in non-migratory species, and than in those species which migrate only a short distance.The factors mainly responsible for decline in bird populations in the countryside would seem to be changes in agricultural practices, together with the general intensification of agriculture, though other factors are also to be considered (evolution of the forest, high population density of ungulates and climate change).


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