Annual and local reproductive variations of a Pied Flycatcher Ficedula hypoleuca population near a subalpine lake in Central Norway

Abstract

The breeding success of the Pied Flycatcher Ficedula hypoleuca was studied for 10 years (1986-1995) in a subalpine area of Central Norway. The data were collected from two nest-box transects, one along the exposed shore of a lake (Lauvsjøen) and the other in the more sheltered, innermost part of the same forest. The results showed: 1) significant annual variations in the breeding success and a decline in the breeding population during the study period, 2) the breeding success of pairs nesting near the shore varied more and was significantly poorer than that of those nesting higher up, 3) the difficulties near the shore were most pronounced when the weather was cold and wet in the early part of the breeding season.