A Potential Tool For Swift Fox (Vulpes Velox) Conservation: Individuality Of Long-Range Barking Sequences

Vocal individuality has been found in a number canid species. This natural variation can have applications in several aspects of species conservation, from behavioral studies to estimating population density or abundance. The swift fox (Vulpes velox) is a North American canid listed as endangered in Canada and extirpated, endangered, or threatened in parts of the United States. The barking sequence is a long-range vocalization in the species' vocal repertoire. It consists of a series of barks and is most common during the mating season. We analyzed barking sequences recorded in a standardized context from 20 captive individuals (3 females and 17 males) housed in large, single-pair enclosures at a swift fox breeding facility. Using a discriminant function analysis with 7 temporal and spectral variables measured on barking sequences, we were able to correctly classify 99% of sequences to the correct individual. The most important discriminating variable was the mean spacing of barks in a barking sequence. Potential applications of such vocal individuality are discussed.