Discussion comments on : ` Approaches for the direct estimation of k and demographic contributions to k using capture - recapture data ’

We thought this was a very nice, comprehensive summary of various approaches to estimating parameters relevant to characterization of population growth ( k ). Here, we will focus on several issues which Nichols & Hines (2002) raise. In fact, part of the measure of the signi® cance of this paper is its breadthÐ it nicely reviews several key approaches to estimation of population growth using data from marked individuals: (i) the JollySeber model and the robust design; (ii) the super-population approach (Schwarz & Arnason, 1996); and (iii) the temporal symmetry approach recently described by Pradel (1996). Nichols & Hines (2002) also force the reader to evaluate the relevant metric for analysis; speci® cally, population abundance, or population growth rate k . Concerning population growth, the authors usefully distinguish between projected and realized growth rate. We brie ̄ y discuss this distinction later. Finally, and perhaps of greatest interest to ecologists, the paper describes several recent advances to partitioning variation in growth into contributions due to survivors and new individuals. This clearly re ̄ ects increasing interest in fully exploring the information contained in encounter histories of marked individuals. Recently renewed emphasis on analysis of recruitment, movement, emigration and so forth are very much motivated by development (or, in some cases, clari ® cation) of methods aimed at partitioning sources of variation in the dynamics of a population. Much of this development has been prompted by previous EURING meetings but