Modelling heterogeneity of survival in band-recovery data using mixtures

Finite mixture methods are applied to bird band-recovery studies to allow for heterogeneity of survival. Birds are assumed to belong to one of finitely many groups, each of which has its own survival rate (or set of survival rates varying by time and/or age). The group to which a specific animal belongs is not known, so its survival probability is a random variable from a finite mixture. Heterogeneity is thus modelled as a latent effect. This gives a wide selection of likelihood-based models, which may be compared using likelihood ratio tests. These models are discussed with reference to real and simulated data, and compared with previous models.