Increased reproductive performance of Red-backed Shrikes Lanius collurio in forest clear-cuts

Abstract

In Sweden, the centre of distribution of the nationally red-listed Red-backed Shrike Lanius collurio has shifted from farmland landscapes to forest landscapes from the 1960s until today. In this study, reproductive performance of Red-backed Shrikes breeding in grasslands in a 75-km2 farmland landscape and clear-cuts in a 75-km2 forest landscape was compared during 1994–1995. During 2003, order of settlement and reproductive performance as well as food abundance and nest predator abundance were assessed in a 3-km2 area in each landscape type. The average number of fledglings was significantly higher in clear-cuts than in grasslands. Furthermore, post-fledgling survival and the probability of replacement clutches following nest failure were likely to be higher in clear-cuts than in grasslands due to the significantly earlier arrival date to clear-cuts. These differences are likely explained by a lower nest predation in clear-cuts compared to grasslands. Today, forest clear-cuts represent the primary habitat of the Red-backed Shrike in Sweden, and probably also elsewhere in the boreal parts of northern Europe.