3.2. Foraging behaviors at different habitats
The bird showed distinct behaviour profiles in deep and shallow habitats. While the duration of a foraging bout was only slightly higher in shallow than in deep habitats (Fig. 4A), the proportion of time spent in each activity classes differed significantly. Specifically, while the bird spent significantly more time in getting ready for fishing in deep waters (Fig. 4B), the time for fishing was significantly greater in shallow waters (Fig. 4C). In addition, time for social interaction was significantly higher in shallow waters (Fig. 4D).
In both habitats, more time was spent for fishing than other activities. In deep waters, the bird spent an average of 62.8%, 36.3% and 0.9% of the foraging time on fishing, preparing, and social interaction, respectively. In shallow waters, the values were 81.8%, 16.8%, and 1.4%. Fishing behaviours were mainly diving (87.3%) in deep water and head-dipping (53.7%) and eye submerging in shallow water (43.1%). Pre-paring behaviours were mainly vigilance in both deep waters (88.6%) and shallow waters (75.5%).