Aerial surveys of Northern Gannet Morus bassanus colonies on Ortac and Les Etacs, Channel Islands, in July 2005, found 2547 and 4862 Apparently Occupied Sites respectively. The total population increased at an average rate of 3.3% per annum over the last 55 years. There may now only be limited room for expansion on Ortac where the rate of increase has declined substantially in recent years.

Atlantic seabirds

CC BY 3.0 NL ("Naamsvermelding")

Nederlandse Zeevogelgroep

Jeremy G. Sanders, & Michael P. Harris. (2005). The Alderney Northern Gannetries — photographic counts of Ortac and Les Etacs, Channel Islands in 2005. Atlantic seabirds, 7(2), 75–82.