We used variations in trapping catch rate as a measure of demographic fluctuation in the host population as this rate would be expected to reflect either changes in population density or changes in spatial behaviour that relate, in some way, to the condition of individuals. Initial pairwise comparisons between trap success on different sampling occasions were based on contingency table analysis (Fisher exact tests). Overall variation in capture rates was then analysed by a linear mixed model (LMM) allowing for correlation between successive trapping intervals (AR1 covariance model).