The gannets of Bass Rock - in pictures

Bass Rock. The gannets arrive on the island in January each year. Photograph: Jeff J Mitchell/Getty Images

Bass Rock is also popular with other seabirds, such as gulls. Photograph: Jeff J Mitchell/Getty Images

It is estimated that up to 150,000 birds nest on the island. Photograph: Jeff J Mitchell/Getty Images

The island is an ideal spot for the birds because it lies 2km offshore. Photograph: Jeff J Mitchell/Getty Images

Gannets live on fish, which they catch by diving under the water. Photograph: Jeff J Mitchell/Getty Images

Gannets normally take five years to reach maturity. Photograph: Jeff J Mitchell/Getty Images

A gannet seizes a fish in its beak. Photograph: Jeff J Mitchell/Getty Images

The birds can reach speeds of 100km/h as they hit the water. Photograph: Jeff J Mitchell/Getty Images

Gannets generally lay only one egg per year, which is chalky blue in colour. Photograph: Jeff J Mitchell/Getty Images

Northern gannets are also found in Ireland, the Faroe Islands, Iceland and Canada. Photograph: Jeff J Mitchell/Getty Images

The birds fly off again in October, destined for Africa. Photograph: Jeff J Mitchell/Getty Images