3.1. General pattern of behaviour profiles
Not surprisingly, the birds spent most time in activities relating to obtaining food including diving, head-dipping, eye-submerging, and vigilance, and food handling, preening and other social activities such as intraspecific interaction took only a fraction of a foraging bout (Table 3).
For each foraging activity, diving took the longest time with mean duration of 13.13 seconds (SD = 7.12) followed by swimming (5.22 ± 6.59s), preening (4.69 ± 4.17s) and vigilance (4.06 ± 2.69s), socializing (3.83 ± 3.12s) and food handling (3.19± 4.77s). While the frequency for head-dipping and eye-submerging were the highest (4.40 ± 5.51 and 5.75 ± 5.48 times/minute, respectively), they took the least time (2.60 ± 0.92s and 1.89 ± 0.07s, respectively). Moreover, the standard deviation (SD) of the attributes (i.e. frequency, duration and proportion) for most behaviours were relatively large comparing with the mean, suggesting the highly variable behavioural profiles of the bird.
Table 3. Summary of the foraging behaviours of M. squamatusduring wintering in Shangqing River, China