Acoustic localisation as a tool to aid monitoring and management of
golden jackals (Canis aureus)
Abstract
Golden jackals (Canis aureus) have rapidly expanded their range across
Europe, raising ecological and socioeconomic concerns. As a highly vocal
species, jackals can be monitored using acoustic surveys, such as howl
surveys or passive acoustic monitoring (PAM), to estimate population
sizes and habitat preferences. A recent advancement in PAM is acoustic
localisation, which estimates the source of sounds by measuring the time
differences of their arrival at multiple synchronised recorders. This
technique can improve the accuracy of population and density estimates
by more precisely calculating distances between jackals and recorders.
However, GPS-synchronised acoustic recorders are costly, which limits
their broader use. In this study, we tested the efficacy of a low-cost
recorder, the CARACAL, for acoustic localisation of golden jackals. We
deployed ten CARACALs over a 10km2 area of the Lunca Mureşului Natural
Park, Romania for seven nights. Alongside passively recording jackal
howls, we also conducted howl surveys. We recorded jackal howls on every
night of the survey and successfully localised 27 jackal and 16 human
howl events, with human howls being localised to within an average of 41
m of their actual location. The average distance between the recorders
and localised jackal howls was just under 1 km, with howls being
detected from as far as 2.5 km away. However, some jackal howls were not
detected by active recorders that were as little as 0.9 km away. Based
on these results, we recommend a conservative spacing of 0.8-1 km
between recorders in future deployments. Overall, this study highlights
acoustic localisation as a valuable tool for improving monitoring
efforts and gathering more detailed data on jackal ecology. This
information could significantly contribute to understanding their
expanding range across Europe, while informing the development of
effective monitoring and management strategies for golden jackals.