Habitat use and diet of skylarks (Alauda arvensis) wintering in an intensive agricultural landscape of the Netherlands

摘要: In recent decades, Skylark (Alauda arvensis) populations in Europe have declined sharply due to agricultural intensification. Insufficient reproduction rates are one reason. Increased winter mortality may also be important, but studies outside the breeding season scarce and mostly limited UK. We studied habitat selection of wintering Skylarks an area Netherlands. monitored between November 2008 March 2009 on 10 survey plots including 77 different arable fields permanent grasslands covering total 480 ha. simultaneously measured food availability, vegetation structure field boundary characteristics. analysed 158 faecal pellets collected potato cereal stubble relate diet seasonal changes availability foraging habitat. show that larger than 4.3 ha, surrounded by no or low a density dietary seeds more 860 m(-2), were most suitable for Skylarks. group densities maize fields. Densities highest soils followed fields, showed strong preference grains, their proportion fell at end November, indicating grains depleted birds had switch less profitable sources, such as weed leaves. conclude landscapes possibly suffer from lack energy-rich sources only few provide sufficient food. Conservation measures should strive improve situation creating food-rich habitats over-winter with rich layer weeds large localised open areas.