“…To assess the costs of reproduction, a biologist will be interested in the probability of breeding in year t, given breeding ψ B,B ¼ 1 À ψ B,NB À Á or not ψ NB,B À Á in year t À 1, as well as assessing any differences in survival probability between breeders ϕ B ð Þ and non-breeders ϕ NB ð Þ. By simply re-expressing the δ, Γ and P x t ð Þ components in terms of the specific state and observation processes of interest, such models can be used to infer the dynamics of conjunctivitis in house finches (Conn and Cooch, 2009), senescence in deer (Choquet et al, 2011), reproduction in Florida manatees (Kendall et al, 2012), interspecific competition between ungulates (Gamelon et al, 2020) and life-history trade-offs in elephant seals (Lloyd et al, 2020). Similar HMMs can also be used to investigate relationships between life-history traits and demographic parameters that are important in determining the fitness of phenotypes or genotypes (Stoelting et al, 2015).…”