Habitat degradation affects song performance in a population of great tits (Parus major)

Abstract

Habitat fragmentation is one of the most important factors responsible for the current global species extinction event. Its effects have been widely studied in forest birds, mainly at the community and/or population level. However, other potential effects have been less studied. For example, because the process of habitat fragmentation usually entails the degradation of the habitat, songbirds may be particularly affected as the transmission of their songs may be altered by this habitat modification. The aim of this study was to analyse the effect of habitat fragmentation on the song performance of a great tit Parus major population. For this purpose, during the breeding season of 2012, we recorded great tit songs of males breeding in large (11-26 ha) and small forest patches (1-2.5 ha). Large patches had a higher tree density and greater tree and grass cover than the small patches. Male size and weight did not differ between patch types nor did breeding success, but some song features did. The strophe length and the peak frequency were longer and lower in large patches. Strophe length was also affected by the density of great tits and was affected differently in large and small patches. Minimum frequency was inversely affected by great tit density. Finally, the date affected peak frequency and pause length. In conclusion, appears that great tit males are capable of choosing their songs to optimize song transmission in each habitat, due to their behavioural plasticity.