In the hole-nesting pied flycatcher, Ficedula hypoleuca, a male may become polyterritorial

after attracting a primary female. However, the female may recognize her mate's song

and attack other females that associate with him. Differences in sound degradation amongst

different habitats and within nestboxes may, therefore, be important for male and female behaviour

since the male may have to move outside female hearing range to avoid harassment,

and the female may have to listen for the mate to be able to locate competing females. This

may be difficult from inside the nest cavity.We used ten common song elements to test sound

degradation with distance in a mixed coniferous and a mixed deciduous forest, measuring

broadcast sounds both inside and outside nestboxes. On average, sound degradation increased

to a larger extent with distance in the deciduous than the coniferous forest. This is consistent

with the shorter polyterritorial distances of flycatchers in the deciduous forest. Furthermore,

song degradation was stronger inside the nestboxes. Being inside may, therefore, reduce a

female's possibility of detecting and recognizing songs. This may be one reason why female

pied flycatchers spend little time within the nest cavity before incubation unlike some other

hole nesting species.