Some Census Methods for Mammals

year to year. Information of this kind is especially needed by the wild-life manager and the conservationist. In practically every study of natural history the taking of one or more censuses would be desirable, if only they could be taken accurately and without too great effort. Unfortunately, it is very difficult to obtain an accurate census of any kind of mammal even on a small area. Many species are shy and avoid the presence of man. In addition, many forms are nocturnal, and nearly all the smaller species make use of burrows in the ground or of holes in trees, in which they spend most or all the daylight hours.