Mark-recapture studies demonstrated that adult Ixodes dammini Spielman, Clifford, Piesman, and Corwin in southern New York successfully overwinter and resume active host-seeking in the spring. Thus, the resulting bimodal peak in autumn and spring appears to reflect temperature-induced activity of the same cohort and not different generations. Adult tick abundance in the field was monitored by counting the number of ticks collected by a domestic dog on routine walks and correcting for the effects of temperature on tick activity. It is suggested that adult abundance, measured independently of ambient temperature, may be an accurate indicator of survival. The field tick abundance curve was negatively exponential (y = e(4.26-0.12x] and significantly different from the survival curve for ticks maintained in the laboratory, which displayed a constant mortality rate (y = -3.7x + 105.5). Body size influenced male survival during the winter, whereas female survival was independent of body size. Greater male mortality in fall and winter resulted in a lower sex ratio in spring.