POPULATION MONITORING OF PLAIN PIGEONS IN PUERTO RICO

摘要

The Plain Pigeon (Columba inornata) was listed as endangered in Puerto Rico in 1970. During 1986-1992 and 1997-2001, we collected point transect survey data to estimate density, population size, and rate of change. Density and population size estimates increased between 1986-1992 and 1997-2001. With a mean density of 0.25 +- 0.06 SE individuals/ha and a mean population size in the area of the surveys of 3,746 +- 892 SE individuals during 1997-2001, we believe that the status of the Plain Pigeon is not as precarious as it was during 1986-1992, when mean density was 0.02 +- 0.003 SE individuals/ha and mean population size in the area of the surveys was 218 +- 42 SE individuals. However, Plain Pigeons are not widely distributed and the loss and fragmentation of second growth forests combined with the effects of hurricanes and other factors may cause their extinction. Because Plain Pigeons have a spatially clumped distribution, we recommend sampling at least 1, 195 points during peak nesting activity (March through June) throughout the island, with at least 526 points covering areas of abundance in eastcentral Puerto Rico, to monitor population changes and evaluate the effectiveness of management actions.