Census Methods for Caribbean Land Birds
Different census methods can be used to survey the distribution of a terrestrial bird species or to monitor population changes. The appropriate method depends on whether the objective is simply to document the presence of a species or to quantify its relative abundance, population density, population trends over time, habitat use, survivorship, or the physical condition of individuals. Once the objective is defined, consideration should be given to selecting a study site, the number of sampling units, the time of day, the time of year, and the experience of field personnel. The various census techniques, and their advantages and disadvantages in the Caribbean Islands, discussed in this paper are: point counts without distance estimation, variable-radius point counts, fixed-radius point counts, point counts for parrots, line transects without distance estimates, variable-distance line transects, strip transects, spot mapping, territory mapping of color-banded birds, mist petting, and use of tape-recorded playback to enhance detectability. For most studies of land birds in the Caribbean, the fmed-radius point count method is recommended.