Recognition of individual European Nightjars Caprimulgus europaeus from their song

Abstract

The European Nightjar is a difficult bird to observe, being mainly nocturnal but also highly mobile, often travelling several kilometres at night to feed. Despite a recent reprieve in the UK, there is international concern about its status. A non‐intrusive monitoring method using vocal individuality therefore has considerable potential. The churring song commonly supposed to mark a territory was recorded from two principal localities in North Yorkshire. A computer program was developed to measure the pulse rates and phrase lengths of the churr and these variables were subjected to discriminant analysis. The pulse rates alone were able to classify 95% of individuals and this improved to 98.5% when the phrase lengths were included. The individual characteristics have been used to suggest movements within a season and the return of one individual to the same territory in three successive years.