Program MARK: survival estimation from populations of marked animals

MARK provides parameter estimates from marked animals when they are re-enco untered at a later time as dead recoveries, or live recaptures or re-sighti ngs. The time intervals between re-encounters do not have to be equal. More than one attribute group of animals can be modelled, The basic input to MA RK is the encounter history for each animal. MARK can also estimate the siz e of closed populations. Parameters can be constrained to be the same acros s re-encounter occasions, or by age, or group, using the parameter index ma trix. A set of common models for initial screening of data are provided. Ti me effects, group effects, time x group effects and a null model of none of the above, are provided for each parameter Besides the logit function to l ink the design matrix to the parameters of the model, other link functions include the log-log, complimentary log-log, sine, fog, and identity The est imates of model parameters are computed via numerical maximum likelihood te chniques. The number of parameters that are estimable in the model are dete rmined numerically and used to compute the quasi-likelihood Ale value for t he model. Both the input data, and outputs for various models that the user has built, are staved in the Results database which contains a complete de scription of the model building process. It is viewed and manipulated in a Results Browser window. Summaries available from this window include viewin g and printing model output, deviance residuals from the model, likelihood ratio and analysis of deviance between models, and adjustments for over dis persion. Models can also be retrieved and modified to create additional mod els. These capabilities are implemented in a Microsoft Windows 95 interface . The online help system has been developed to provide all necessary progra m documentation.