Song variation of a native songbird in a modified habitat by invasive plant.

Habitat structure has been considered as an important factor affecting the acoustic evolution of birds, and bird songs are increasingly affected by artificial environmental variation. Invasive plants sometimes can dramatically alter native habitats, but the song variation of native songbirds migrating into invaded habitats has received little attention. The invasion of smooth cordgrass Spartina alterniflora in the coastal wetlands of eastern China has drastically altered the vegetation structure and some small passerines have begun to use invaded habitats to breed. In this study, we compared the song type prevalence and the song characteristics of male plain prinia Prinia inornata to identify differences in vocal behavior between native and invaded habitats. We also tested for differences in vocal behavior in relation to singing perch and wind speed variation between different habitats. The results indicated that males of plain prinia in invaded habitats sang shorter songs than those in native habitats and had a lower song diversity. The homogeneous vegetation structure and higher wind speed in invaded habitats likely leads to males changing the traditional perched singing style. The song variation may be related to the founder effect, the alteration of vegetation structure and microclimate in invaded habitats. This finding highlights the need for better understanding the behavioral evolution of native species in the process of adapting to the invaded habitat. In the future, experimental manipulation is needed to ascertain how the invasive plant drove these vocal behavior changes of native songbirds.