Effects of Meteorological Factors on the Expression of Nesting Behaviour in the Sulawesi Babirusa ( Babyrousa celebensis)

Abstract

The impact of environmental stimuli on the expression of nesting behaviour of Sulawesi babirusa (Babyrousa celebensis) was explored over a period of 1339 days from 01 st August 2006 until 31 st March 2010 in a large animal enclosure on Bali, Indonesia. We found that nest building behaviour and the re-use of sleeping nests occurred more frequently in the dry season than the wet season and was clearly influenced by both a drop in the ambient temperature and an increase in wind speed. Additionally, net effective temperature (NET) computed from a combination of ambient temperature, relative humidity, and wind speed indicated a close relation to the nesting behaviour frequency; a decreasing trend of the expression rate of nesting behaviour with increasing NET in the early evening. Moreover, the trend of the expression rate by 12-hr NET fluctuation from 05:00 hr to 17:00 hr was also found out in all seasons. Meanwhile, 24-hr rainfall had a negative impact on the expression rate. These findings suggested that NET was a useful meteorological index to discuss the motivation to exhibit the nesting behaviour of babirusa, and also babirusa probably found thermal comfort in the sleeping nest.