Spatial relationships of Adelie penguin colonies: implications for assessing population changes from remote imagery

The relationship between colony area and population density of Adelie penguins Pygoscelis adeliae was examined to determine whether colony area, measured from aerial or satellite imagery, could be used to estimate population density, and hence detect changes in populations over time. Using maps drawn from vertical aerial photographs of Adeliepenguin colonies in the Mawson region, pair density ranged between 0.1 and 3.1 pairs m^-2, with a mean of 0.63 t 0.3 pairs m^-2. Colony area explained 96.4% of the variance in colony populations (range 90.4-99.6%) for 979 colonies at Mawson. Mean densities were not significantly different among the 19 islands in the region, but significant differences in mean pair density were observed among colonies in Mawson, Whitney Point (Casey, East Antarctica) and CapeCrozier (Ross Sea) populations. The relationship between colony areaand population may be locality- and/or species-specific, and a robust data set is required to validate the relationship. [ABSTRACT FROM AUTHOR]