This study aims to investigate if patterns of immigration by voles into removal plots on the third day of trapping are evident in the grey-sided vole, and if altering the number of traps at each station will result in increased precision of the vole abundance estimate. Traps were placed using the small quadrat method, with one, three, or five traps placed at each corner. Traps were checked twice a day for five days. Mixed-effect models were used to investigate the relationship between the number of traps and the length of time the traps were out on the abundance index. There was no difference between having three or five traps. Having one trap resulted in an inflated estimate. Five traps had the highest number of successful trapping events, reducing the number of zeros in the data set and leaving fewer individuals unaccounted. There was a peak in catches on the third day, driven by younger individuals and by males. These are suspected immigrants that are exploiting the territories left by individuals trapped in the first two days, suggesting this is not a closed system.