This research mainly focuses the speed of fecal pellet decomposition of Formosan Sika deer. In my research, the population sizes of the deer in restoration areas were estimated with dropping counts and clearance method. According to my investigation into the speed of fecal pellet decomposition in specific restoration area, I found 223 fresh excrements on two transection lines in restoration 1 and another line in restoration 4. The fecal pellet decomposition period in wet season was 45 days (n=56), and that in dry season was 98 days (n=167). The average was 85 days (n=223). Hence there were 11sika deer in restoration area one and 8 in restoration area four by my estimate of using dropping counts. Besides, from April 2009 to March 2010, there were about 96 piles of fecal pellet per hectare every month in wet seasons and 254 in dry seasons in restoration area one when clearance method was used to keep track of excrements every month. However, there were 38.7 piles/ha per month in wet seasons and 173.3 piles/ha in dry seasons. It is clear that the speeds of fecal pellet decomposition were different in wet and dry seasons. Therefore, I attributed the difference of speeds to the rainfall. I estimated that there were about 17 sika deer in restoration area one and 9 in restoration area four in dry seasons by using clearance method.
However, there were 20-30 deer in restoration area one and 15-24 in restoration 4 when automatic cameras were used as an auxiliary tool for estimates. The population sizes from dropping counts and clearance method were smaller than those from the use of automatic cameras. This result may be attributed to deer’s oestrus in dry seasons because the bucks sika deer’s territorial behavior may lower their uniform distribution. In addition, the population size may be underestimated since I might have missed some fecal pellets when I used dropping counts method.