For example, age structure of the population may be important, or some individuals may have higher probability to be caught than others. Another problem arises if the population has no boundaries. The area covered by the grid should be much larger than the average distance of animal dispersal. Because the biology of different species is variable, it may be necessary to modify the capture-recapture model. Removal method Removal method is based on intensive trapping of animals in an isolated area.
Migration is prevented by some kind of barriers.
It is assumed that there are no births or natural deaths of organisms. The proportion of animals captured each day is the same.