Using Age Structure Data from Changing Populations

(1) Estimating survival from age structure data is a widely used technique subject to serious biases if the population was changing when the observed age structure developed. (2) Simple modifications of the basic equations for population dynamics make it possible to continue use of the efficient 'Chapman-Robson' methods in such cases. Three examples, in deer and grey seals, demonstrate the procedure. (3) An independent estimate of the rate of population change is needed to estimate survival, but relative survival of the younger age-classes can be estimated without knowing rate of population change.