Effects of time of day, visitor pressure and weather on the behaviour of captive American bison Bison bison

Abstract

The study of bison in zoos can provide insights about the behaviour of this species with application for the management of herds held in captivity for both public display and bison farming. The aim of this study was to describe and investigate the behavioural budget of American bison in captivity, specifically focusing on how these behaviours may be influenced by time of day, visitor pressure and weather. Four bison Bison bison (two male and two female) at the Zoo Aquarium Madrid in Spain were video monitored for 27 days (May 2022) by three solar-powered cameras. From the footage collected, five behaviours were hourly annotated: lying, standing, moving, eating and drinking. The corresponding meteorological data (temperature, relative air humidity, temperature humidity index, wind speed, barometric pressure and solar radiation) were also measured. Data analysis examined bison behaviour and its relationship with time of day (diurnal, nocturnal), visitor pressure (low, high) and meteorological data divided in days by range of observed weather conditions (lower, upper). Bison spent most time lying, followed by standing, moving, eating and drinking. Bison spent more time lying at night and ate more during the day. The animals spent more time drinking during high visitor pressure. Behaviour was affected by weather; increased temperatures and humidity reduced movement time, while elevated barometric pressure was related with more drinking time. Lower pressure and increased solar radiation were associated with less moving/standing time and more lying time, respectively. In summary, bison behaviour was influenced by time of day, visitor pressure and weather parameters.