(a) Call rates
The call rate of low-amplitude calls for lactating females with calves (7.13 ± 2.0 calls h−1) was significantly higher than the call rate of high-amplitude GLMM odds ratio = 0.12 ± 0.06, The GLMM revealed no statistically significant differences compared to other age/sex classes; however, non-lactating ani- mals showed a trend of higher call rates for high-amplitude calls (3.21 ± 2.29 calls h−1) and lower rates of low-amplitude calls (0.80 ± 1.15 calls h−1) compared to lactating females with calves. This result is likely owing to the unbalanced data (more lactating females sampled), small sample size and skewed data owing to a small number of outliers (table 1).
(b) Call type usage
The results of the GLMM reveal that low-amplitude calls comprise a significantly larger proportion of the call reper- toire for lactating females than for non-lactating whales (table 2 and figure 2). [1]