Farmland birds on forest clear-cuts: Liked by some, avoided by others

Abstract

Many bird species typical to farmland have declined in numbers in recent decades. Some farmland bird species occur outside farmland in other open man-made habitats, such as forest clear-cuts. Given that in Sweden the total area of clear-cuts (5–6 %) almost equals that of farmland (8 %), clear-cuts have the potential to be an important habitat for some farmland birds. We investigated how bird community composition and species abundance on Swedish clear-cuts varied with geographical region, clear-cut characteristics and the surrounding landscape, with special focus on farmland species. Based on short visits in 2017–2019, we surveyed the occurrence of birds on 300 representative clear-cuts in Sweden, including six regions and 1300 km of latitude. We counted 1170 birds of 66 different species, including 10 out of 15 bird species in existing farmland bird indicators. Both bird community composition and species abundance varied with clear-cut size, age, vegetation height, region and proportion of nearby farmland, depending on species’ ecology. All six farmland species being proportionally common on clear-cuts are, when in farmland, dependent on residual habitats such as pastures and field borders with bushes and trees. In contrast, a third of the dedicated farmland species were scarce in clear-cuts, probably avoiding them because of predator-related avoidance of forest edges and/or a lack of suitable nest sites or food resources. To determine the full importance of forest clear-cuts for farmland species, and potentially make them more favourable for farmland birds, more studies are needed on the reproductive success on clear-cuts and which site features make them suitable habitat. This study did not determine the consequences of clear-cuts for forest birds across the forest cycle, consequences which needs to be balanced against any gains for farmland birds.