Preferenser för olika fälttyper hos häckande jordbruksfåglar – en litteraturstudie

Abstract

This study compiles results from studies of preferences for different arable field types for 31 farmland birds. Most species avoided autumn sown cereals and preferred set-asides, especially rotational set-asides. The preference patterns were more complex for spring-sown cereals and cultivated grasslands. Cultivated grasslands were preferred by omnivores and insectivores and avoided by herbivores and herbivores/insectivores. A similar, but weaker, pattern was found for spring-sown cereals. Food preferences seemed to be more strongly associated to field type preferences than to other ecological characters. However, these are not independent of each other; for instance, eight of 10 insectivores are ground nesters and nine insectivores have small or intermediate territories. For most species, set-asides restricted to edge zones and field borders would be beneficial. However, for open field species (e.g. Skylark), large fields with set asides are needed. It is probable that certain threshold levels in areas of set-asides are needed before effects on a national or regional level could be seen. Furthermore, a time lag of several years should be expected before effects of increased areas of set-aside could influence population sizes.