Lutra 46(1)_Bankert et al_2003

A review of the transect method by comparing it with three other counting methods to estimate rabbit (Oryctolagus cuniculus) density

In dune areas in the Netherlands, the standard method for estimating rabbit (Oryctolagus cuniculus) populations is by counting the number of rabbits that can be seen in the headlights of a car along standard trans­ects. This paper evaluates whether estimated rabbit densities derived from this method represent the density of rabbits in the hinterland. Three alternative methods were employed: the pellet count, the spotlight count and the burrow count. While the transect method could only be used on the transects, the others were used on both the transects and in the hinterland and these results were compared with those from the transect counts. The burrow count did not reveal any clifference in the number of rabbits on the transects and in the hinterland. While the spot­light count and the pellet count showed a significant clifference with more rabbits being estimated in the hinter­land. The results of the pellet count are the most reliable since the results are not influenced by disturbance or weather circumstances. The number of rabbits estimated on the transects with this method was more or less simi­lar to the clensity estimates of the transect method. The pellet count showed that there were 30% more rabbits in the hinterland than along the transect. Hence extrapolation of data of the transect method to the hinterland under­estimates the number of rabbits in this area. lt should be noted that these conclusions are based on a situation with a very low population density and it is possible that other results will be founcl in situations where the population density is much higher.