Flexible models for analysing ring recovery data to estimate survival rates

We describe MULT, a flexible procedure for analysing ring recovery data. The procedure starts with parametric structures similar to, but more general than, those described by Brownie et al. (1985). Particular models, including those in Brownie et al. (1965), can be obtained by imposing constraints on the general parametric structures. Examples of models that are available in MULT include: analysis of ringing data when no birds are ringed in some years; analysis of twice-yearly ringing to estimate interval survivorship; and analysis of ringing data when survivorship is hypothesised to be a function of a covariate measured annually. We use North American ringings of Atlantic Brant (Branta bernicla hrota), Mallard (Anas platyrhynchos), and Ring-necked Ducks (Aythya collaris) to illustrate the above models. MULT is a menu-driven, IBM-PC compatible program, and is available from the second author.