The Biological Investigations of Marine Antarctic Systems and Stocks (BIOMASS) programme was a co-ordinated international science programme undertaken to study Antarctic marine living resources between 1981 and 1985. The programme was organised by the Scientific Committee on Antarctic Research (SCAR) and brought together ten countries involved in Antarctic Research. This programme focussed primarily on Antarctic Krill but also made records of bird observations, fish (including Ichthyoplankton) and various oceanographic data including chlorophyll-a measurements. This dataset contains all data collected on bird observation made during the BIOMASS programme. These data were origianlly compiled by the BIOMASS Data Centre in Cambridge and have subsequently been made available as part of a data rescue project funded by EUR-OCEANS.