The emergence of Bayesian methodology has facilitated respondent-level conjoint models, and deriving utilities from choice experiments has become very popular among those modeling product line decisions or new product * Co-chairs. Author order is alphabetical. ALLENBY ET AL.introductions. This review begins with a paradox of why experimental choices should mirror market behavior despite clear differences in content, structure and motivation. It then addresses ways to design the choice tasks so that they are more likely to reflect market choices. Finally, it examines ways to model the results of the choice experiments to better mirror both underlying decision processes and potential market choices.

Movement patterns of sea otters (Enhydra lutris) were followed by daily monitoring of 40 individuals with implanted radio transmitters. Otters of all age and sex classes were most often found within 1–2 km of their locations on the previous day. However, individuals often remained within a small area for an extended period and then suddenly moved a much greater distance within a short time period. There were significant differences among age–sex classes, but not months, in the mean monthly distances between successive daily locations and between extreme locations of individual otters. There were significant differences among both age–sex classes and months in the harmonic mean distance deviation. For all three measures, juvenile males tended to move the greatest distances. Adult males tended to be more sedentary than adult females over the short term, but traveled over greater distances in the long term. Individuals within age–sex classes had different movement patterns, and individuals often had different movement patterns during the same month in successive years. Estimates of the area used by individual otters during a single 24-h period (6.9–1166.4 ha) overlapped previous estimates of home-range size based on much longer time periods.

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1991. Age-specific reproduction in feral horses. Can. J. Zool. 69: 738-743. Two age-specific reproduction schedules were constructed for feral horses (Equus caballus) on the basis of lactation status of 14 788 females captured during herd reduction programs and pregnancy rates of 667 horses determined by serum progesterone assays. The probability of detecting lactation progressively decreased for females captured further from the foaling season, indicating that these data resulted in substantial underestimates of true foaling rates. A third reproductive schedule was, therefore, constructed on the basis of a subsample of 1144 horses captured immediately after the foaling season in June. Characteristics common across all three data sets were first reproduction at age 2, an increase in the proportion of females foaling through age 6, highest foaling rates from 6 to 15 years, and a gradual decrease in foaling rates of females > 15 years. Variability in the proportion of reproductively active females in each age-class was detected among populations and among years within a population; however, the general trend was high reproductive rates, with 80-90% of the prime-age females foaling. The reproduction m$el suggested by L. L. Eberhardt, provided a close mathematical approximation of the observed age-specific changes in foaling rates, providing a useful tool for the construction of reproduction schedules required for age-structured population models.GARROTT, R. A., EAGLE, T. C,, et PLOTKA, E. D. 1991. Age-specific reproduction in feral horses. Can. J. Zool. 69 : 738-743. Nous avons klabork deux calendriers de reproduction spkcifiques a l'ige chez des chevaux sauvages (Equus caballus), calendriers basks, d'une part sur la lactation chez 14 788 femelles capturkes au cours de programmes de rkduction des troupeaux, d'autre part sur les taux de grossesse dkterminks par des tests sur la progestkrone skrique de 667 chevaux. La probabilitk de dktecter la lactation diminiue progressivement dans le cas des femelles capturkes plus longtemps aprks la saison de mise-bas, ce qui indique que les rksultats comportent des sous-estimations importantes des taux rkels de mise-bas.

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