Cat vocal behavior, in particular, the vocal and social behavior of feral cats, is poorly understood, as are the differences between feral and fully domestic cats. The relationship between feral cat social and vocal behavior is important because of the markedly different ecology of feral and domestic cats, and enhanced comprehension of the repertoire and potential information content of feral cat calls can provide both better understanding of the domestication and socialization process, and improved welfare for feral cats undergoing adoption. Previous studies have used conflicting classification schemes for cat vocalizations, often relying on onomatopoeic or popular descriptions of call types (e.g., “miow”). We studied the vocalizations of 13 unaltered domestic cats that complied with our behavioral definition used to distinguish feral cats from domestic. A total of 71 acoustic units were extracted and visually analyzed for the construction of a hierarchical classification of vocal sounds, based on acoustic properties. We identified 3 major categories (tonal, pulse, and broadband) that further breakdown into 8 subcategories, and show a high degree of reliability when sounds are classified blindly by independent observers (Fleiss’ Kappa K = 0.863). Due to the limited behavioral contexts in this study, additional subcategories of cat vocalizations may be identified in the future, but our hierarchical classification system allows for the addition of new categories and new subcategories as they are described. This study shows that cat vocalizations are diverse and complex, and provides an objective and reliable classification system that can be used in future studies.

Context. Synchronised acoustic recorders can be used as a non-invasive tool to detect and localise sounds of interest including vocal wildlife and anthropogenic sounds. Due to the high cost of commercial synchronised recorders, acoustic localisation has typically been restricted to small or well-funded surveys. Recently, low-cost acoustic recorders have been developed, but their efficacy has yet to be compared to higher specification recorders.Aims. This study aimed to compare the efficacy of a newly developed low-cost recorder, the CARACAL, with an established, high-end recorder, the Wildlife Acoustics Song Meter (SM).Methods. We deployed four recorders of each type in a paired set-up across five nights in Wisconsin, USA. We manually identified domestic dog (Canis familiaris), grey wolf (Canis lupus), coyote (Canis latrans), and barred owl (Strix varia) calls on the recordings then compared the ability of each recorder type to detect and localise the vocalising animals.Key results. The CARACALs were less sensitive detecting only 47.5% of wolf, 55% of coyote, 65% of barred owl, and 82.5% of dog vocalisations that were detected on the paired SMs. However, when the same vocalisations were detected on both recorders, localisation was comparable with no significant difference in the precision or maximum detection ranges. Conclusions.Low-cost recording equipment can be used effectively for acoustic localisation of both wild and domestic animals. However, the lower sensitivity of the CARACALs means that a denser network of these recorders would be needed to achieve the same efficacy as the SMs. Deploying a greater number of cheaper recorders increases the labour time in the field and the amount of data to process and store. Thus, there is trade-off between cost and time to be considered. Implications.The ability to use low-cost recorders for acoustic localisation provides new avenues for tracking, managing and researching a wide range of wildlife species. At present, we suggest that CARACALs are more suited to monitoring species that have small home ranges and high amplitude vocalisations, and when a large time investment for in situ equipment checks and data processing is feasible.

Context. The ecology of cryptic animals is difficult to study without invasive tagging approaches or labour-intensive field surveys. Acoustic localisation provides an effective way to locate vocalising animals using acoustic recorders. Combining this with land cover classification gives new insight into wild animal behaviour using non-invasive tools. Aims. This study aims to demonstrate how acoustic localisationcombined with high-resolution land cover classificationpermits the study of the ecology of vocalising animals in the wild. We illustrate this technique by investigating the effect of land cover and distances to anthropogenic features on coyote and wolf vocal behaviour. Methods. We collected recordings over 13 days in Wisconsin, USA, and triangulated vocalising animals' locations using acoustic localisation. We then mapped these locations onto land cover using a high-resolution land cover map we produced for the area. Key results. Neither coyotes nor wolves vocalised more in one habitat type over another. Coyotes vocalised significantly closer to all human features than expected by chance, whereas wolves vocalised significantly further away. When vocalising closer to human features, coyotes selected forests but wolves showed no habitat preference. Conclusions. This novel combination of two sophisticated, autonomous sensing-driven tools permits us to examine animal land use and behavioural ecology using passive sensors, with the aim of drawing ecologically important conclusions. Implications. We envisage that this method can be used at larger scales to aid monitoring of vocally active animals across landscapes. Firstly, it permits us to characterise habitat use while vocalising, which is an essential behaviour for many species. Furthermore, if combined with additional knowledge of how a species' habitat selection while vocalising relates to its general habitat use, this method could permit the derivation of future conclusions on prevailing landscape use. In summary, this study demonstrates the potential of integrating acoustic localisation with land cover classification in ecological research.