The search cost in mate choice of the pied flycatcher

Polygyny and Breeding Success of Pied Flycatchers Nesting in Natural Cavities

Many hole-nesting passerine birds accept, or even prefer, nest boxes. Hence most of our knowledge about the breeding biology, population dynamics, life-history evolution and so forth of such species comes from nest box studies. This, in some cases, might lead to erroneous conclusions. For example, breeding density in nest box areas may often be much higher than in the natural situation (e.g. von Haartman, 1971), possibly leading to unnatural density dependent effects. Furthermore, the use of nest boxes may reduce predation risks (e.g. Nilsson 1975, 1984 a,b, Moller 1989), while the routine procedure of cleaning boxes after each breeding season may reduce the number of parasites, thus affect…