In 1940, a single pair of Northern Gannets nested on Les Etacs. The colony grew, partly through lack of disturbance from any fishing activity during World War Two, and by 2011, there were 5765 pairs of gannets on Les Etacs, and a further 2120 pairs on Ortac. These colonies account for 2% of the world population. Research in 2011 using GPS satellite tags found that Alderney”™s gannets use three main foraging areas: the local bay of Mont St Michel, the French coast towards Le Havre, and the south coast of England. They frequently make round trips of 200 to 300 km to locate their food. Gannets feed primarily on fish such as mackerel, sand eels and herring, which they find by diving to depths of up to 20 metres or scavenging along the surface of the sea. They seem to have prospered from the EU discard policy under which fisherman are required to return catches outside the terms of their quotas. Darker coloured juvenile birds are unable to roost on the heavily defended nest sites, and will only reach maturity after four to five years. These young birds are vulnerable when taking their first flights from the nest in early autumn, sometimes finding it difficult to take off from the surface of the sea.