Nesting of the willow warbler (<Emphasis Type="Italic">Phylloscopus trochilus</Emphasis> Linnaeus, 1758) (Sylviidae,Aves) in natural and urban habitats of Karelia

Our study was carried out within the framework of the project “Ecological and Behavioral Adaptations of Birds Typical for Natural Habitats to the Urban Environment.” The willow warbler was chosen as a model object in this investigation aimed to provide comparative analysis of the bird breeding behavior in natural and urban areas of Karelia. The breeding dates, preferred biotopes and nest sites, and the clutch characteristics and reproductive relations of the willow warblers were found to be similar in various conditions, whereas their flight distances were shorter and the alarm call intensity was higher in urban habitats than in forest ones. Possible explanations for the results obtained are given.