Steps to Parameter Redundancy in Age-Dependent Recovery Models

SUMMARY Recovery data result when marked animals are found dead and their marks are reported. Large banks of such data exist for many species of birds ringed as young. It is often important to include in stochastic models for such data a degree of age variation in both the annual survival and the reporting probabilities. We show how to determine by inspection whether such models are parameter redundant, which identifies the cause of the parameter redundancy when it occurs. We also show how the results extend to a useful example of a model incorporating both time- and age-dependent probabilities.