Behavioural responses of wintering black-faced spoonbills (Platalea minor) to disturbance

Abstract

Context Behavioural responses can be used to understand the impacts of disturbance on animals and to develop management strategies, and there is considerable conservation interest in quantifying the effects of disturbances on wild animals. Aims We seek to formulate a management plan for the endangered black-faced spoonbills (Platalea minor) in a non-breeding ground, on the basis of their behavioural responses to different types of stimulus categorised by threat level (threatening vs non-threatening) and human involvement (anthropogenic vs natural). Methods We documented 16 stimuli from 379 disturbance events through continuous observation on 31 daily selected focal individuals, and estimated flight distances caused by human approach under different conditions at a non-breeding site in Korea. Key results The spoonbills showed the strongest behavioural response to the non-threatening anthropogenic stimuli, and human approach followed by motor vehicles caused longer responses per event than did any other type of disturbing stimulus. Flight distance caused by human approach varied depending on conditions; inactive spoonbills in mixed-species associations started to flee at the greatest distance (197.4 m, with a 50% probability), whereas the spoonbills in a single conspecific flock were the most tolerant of human approaches, regardless of their activeness (61.0–61.7 m, with a 50% probability). Conclusions Human approach had been identified as the most important disturbing stimulus that should be controlled as a priority. We also suggest that black-faced spoonbills benefit from the presence of other waterbirds and exploit them as an early warning system. Implications The tolerance of sympatric species as well as the behavioural response of target species should be considered when a buffer area for wildlife management, particularly against human disturbance, is planned. How the site has been used and what the species composition is are still important components for the design of safe refuges and roosts.