Il rampichino comune, Certhia brachydactyla, sul Montello: andamento dell'attività di canto e della risposta al playback nella stagione riproduttiva (Passeriformes: Certhiidae)

The population of Short-toed treecreeper (Certhia brachydactyla) inhabiting the Montello hill (Venetian Pre-Alps) was studied to evaluate the temporal variation of both song activity and reaction to playback during the breeding season. Eight sample-plots were visited repeatedly between mid February and mid July, performing a total of 133 hours of census and 240 playback tests. Short-toed treecreepers were detected through spontaneous vocalizations, with an average frequency of 0.8 contacts/hour (0.6 contacts/hour by song activity only). The highest frequency of contacts for all kinds of vocalizations was registered between the end of April and the beginning of May (throughout March and April for songs only). Out of all playback tests performed inside breeding territories, 46% induced reaction, with the highest frequency during April. Induced vocalizations began most frequently within the first half minute since the beginning of playbacks. From February to July, reaction time increased gradually both in mean and range of variation, the frequency of induced songs decreased whereas that of induced calls increased.