The winter distribution of seed-eating birds: habitat structure, seed density and seasonal depletion

To understand the reasons for population change we need to understand the mechanisms through which it occurs. Throughout western Europe there have been declines in farmland birds. These declines have been paralleled by major changes in agricultural management, which have resulted in major changes in habitat structure. This paper describes the habitat selection at two scales (within and between fields) of a number of seed-eating farmland birds. Habitat preferences for most species were related to the density of seeds present, which differed markedly between habitats. Seed density declined with distance from hedgerow in cultivated fields but not stubble Fields. Yellowhammers were restricted to foraging close to hedgerows, whilst skylarks foraged in the centre of fields, but moved closer towards the edges as the winter progressed and seed densities declined. This work has clear consequences for agricultural management and the conservation of declining bird populations.