Breeding status shapes territoriality and vocalization patterns in spotted owls

Vocal territory defense can vary within a species due to many factors such as sex and breeding status, influencing territory size and thus population density across a landscape. Therefore, understanding what influences variation in territorial vocalizations can help to illuminate trade-offs between territoriality and other life history demands, which benefits our general understanding of animal ecology as well as helps to inform emerging passive acoustic monitoring approaches. Here, we investigated how sex and breeding status affected territoriality and vocal behavior in the California spotted owl (Strix occidentalis occidentalis) in the Sierra Nevada, California, USA, using high-resolution acoustic/GPS tags. We discovered that territorial vocal behavior was related to breeding status and to a lesser extent sex. Breeding owls with fledged young had a less diverse vocal repertoire, produced fewer and quieter territorial calls, and typically called only when close to their nest. Males wer...