Data are of numbers of breeding pairs of Adelie penguins(Pygoscelis adeliae)in the Ross Sea region colonies counted from aerial photographs. Photographs were taken from either a helicopter or from a C-130 Hercules. Photos were printed, populations counted, catalogued and filed. Since 2004, digital photography was used and in 2011 semi-automatic penguin counting software was developed to speed up ... the counting and validation process. Ross Island colonies were censused annually, colonies along the Victoria Land coast were censused as logistics allowed. Data collection started in 1981 in response to a proposed krill fishery and is ongoing. The aim was to locate all Adelie penguin colonies in the Ross Sea Region, and to count the numbers breeding at each from aerial photographs. The work attempts to relate annual changes in numbers of penguins breeding and their breeding success to weather, sea ice and other climate parameters in order to distinguish between responses due to natural events and those induced by commercial exploitation (such as fishing) or human disasters. A total of 39 colonies were found in the Ross Sea. The work is ongoing.