Against a background of apparent demographic increase during May-December 2008, significant decreases in trapping rate with respect the immediately preceding trapping occasions (either 1 or 2 intervals distant) were only recorded immediately after the detection of extreme expression clusters (Figure 2 ). LMM analysis of trapping success data against time (days), allowing for positive autocorrelation between successive trapping sessions, suggested a highly significant increasing trend across May to December (LMM, P,0.001; parameter estimate = 0.0013060.00035 catch rate day 21 ). A 2-level factor coding the two time intervals following the first detection of each extreme expression cluster (vs Using eye lens weight as an index of age, plots of lens weight with respect to time allowed unambiguous identification of overwintered (1 + ) and young-of-the-year (0 + ) cohorts in 2008 and also in a retrospective analysis of animals sampled at Cotgrave Forest by Jackson et al. [18] in 2007 ( Figure 4 ). Cohort dynamics differed in 2008 compared to 2007 by an abrupt earlier disappearance of 1 + animals, in late June, that was followed by a very large proportional contribution to the population by new recruits (0 + individuals with the lightest eye lenses, ,0.014 g) (Figure 4 ).