Testing hypotheses and estimating survival from capture histories with CR

International audienceThanks to the progress of the methodology for survival analysis of capture± mark± recapture data, today biologists become able to test the individual or environm ental factors that are likely to affect survival and, relatedly, they can estimate survival with a model that describes satisfactorily and ef® ciently the population and the experiment. Assessment of ® t, adjustment and model selection are the main tasks in the process. Several computer programs exist with complementary abilities in those respects and, most often, one must use successively several of them in a single analysis. As there is no standardized presentation of the data, the transition from one program to another is not particularly easy. C R is a software package that intends to alleviate those dif® culties by putting together some of the most popular programs and providing passageways between them. W e explain how a typical analysis is carried out with CR and insist on thē exibility that can be achieved with SURGE , a program for designing and ® tting survival models which is an integral part of CR. A real example is treated for illustration

Selection of survival and recruitment models with SURGE 5.0

International audienceThe great flexibility of capture-recapture models to estimate survival and recruitment parameters is described. Recruitment models appear as analogous to survival models applied to capture histories reversed in time. The available flexibility is used at its best by basing model selection on the minimization of Akaike's information criterion within a set of biologically plausible models. However, to proceed to model selection, one needs to determine the number of identifiable parameters. We explain how SURGE version 5.0 (available on the Internet by anonymous ftp from ftp.cefe.cnrs-mop.fr) makes it possible to fit survival and recruitment models and determines numerically how many and which parameters are concerned with identifiability problems. Model selection for survival and recruitment models is illustrated using European Dipper Cinclus cinclus data. The advantages and shortcomings are discussed