A response to Corkeron and Connor. L. Baraff, W. Koski and G. Miller. J. Cetacean Res. These are tested on both simulated data and actual data from 1985 and 1986 photographic studies. Initially a multinomial model that accounts for unmarked whales is used.
Variance is estimated using the parametric bootstrap.
In the cases considered, the variance estimators perform similarly to previously used delta method based estimators in terms of confidence interval coverage, as long as log-normal rather than symmetric confidence intervals are used for the latter. Further models are developed to account for heterogeneity in capture probabilities and non-random sampling caused by age segregation. Deecke, V.B., J.K.B. Ford, and P. Spong. Variation in vocal signals among populations and social groups of animals provides opportunities for the study of learning and its importance in generating and maintaining variation in behavioural traits. We use a neural network-based index of acoustic similarity to identify mechanisms of call differentiation.