Number of nearby visitors and noise level affect vigilance in captive koalas

Understanding human-animal interactions is particularly important for institutions that display animals to the public due to the frequent, and sometimes intense, interactions with unfamiliar humans. Past research has shown that visitors can have a negative impact on the welfare of a wide range of captive zoo species through an activation of the stress response, which influences energy metabolism. The koala (Phascolarctos cinereus) evolved on a specific diet of extremely low energy content and is therefore likely to be particularly susceptible to any effects from stress. However, the knowledge of visitor effects on captive koala behaviour and welfare is almost non-existent. The effects of visitor number (Study 1) and visitor noise (Study 2) were investigated in a population of captive koalas. In Study 1, behavioural observations were conducted on koalas across a total of eight days: four days of high visitor attendance and four days of low visitor attendance. Scan sampling was used every 2 min to record individual koala behaviour, position in enclosure and proximity to the boardwalk. The number of visitors within a 5 m radius on the boardwalk, hereafter referred to as 'nearby visitors', was also recorded for each scan. In Study 2, the effect of visitor noise was investigated using audio recordings of visitor noise taken from the study site in three levels of treatment (No visitors, Quiet visitors and Loud visitors). Each koala was randomly allocated each noise treatment once daily over eight days and the presence or absence of vigilance behaviour was recorded. Study 1 demonstrated that an increase in the number of nearby visitors, but not total daily visitor number, resulted in increased time spent vigilant in the koalas. Study 2 showed that an increase in visitor noise treatment resulted in increased time spent vigilant in the koalas. These results show that koalas do respond behaviourally to visitors, supporting the value of behavioural observations as a monitoring tool to assess visitor-related disturbance in koalas. The welfare implications of these behavioural changes remain to be determined, as well as adequate management strategies to minimise negative visitor effects.