Herring gull (Larus arentatus, HERG), great blue heron (Ardea Herodias GBHE), double-crested cormorant (Phalacrocorax auritus, DCCO) and ring-billed gull (Larus delawarensis, RBGU) have been monitored in Pukaskwa National Park since 1977 as part of the colonial waterbird monitoring program. A complete count of active nests on islands found along the ~120km of coast of Pukaskwa is conducted based on the Canadian Wildlife Service (CWS) protocol. The nest count is carried out during the peak of breeding over a period of 2-3 weeks. From 1977 – 1981, surveys were conducted annually and used an island numbering system (Old Colony Number in datasheet). From 1989 – 2013 surveys occurred at irregular intervals and the numbering system changed (Colony Number in datasheet), partly to follow the CWS naming convention. Since 2013, surveys have been conducted every two years (2013, 2015 and 2017). Data from these surveys are used to monitor the colonial waterbird populations within Pukaskwa.