A colony of Northern gannets on Bass Rock has been named the largest in the world following the latest count.

The colony on the island in the Firth of Forth has overtaken populations on St Kilda and Bonaventure Island, which is off Canada, experts said.

Researchers found 75,000 apparently occupied sites (AOS) on Bass Rock when they counted the birds last year, a 24 per cent increase on a similar count in 2009.

Each site can represent a breeding pair and their chick, with more than 150,000 birds expected on the island during this year's breeding season.

The count was carried out by independent researcher Stuart Murray in conjunction with the Centre for Ecology and Hydrology .

Mr Murray said: "The colony was photographed from the air on June 23 2014. Conditions were excellent, with no wind and a high cover of thick cloud which obscured the sun, reducing the glare from all these startlingly white birds. The images were later viewed on computer screens for counting and each occupied site was blocked out as it was counted.

"Interestingly, the most dramatic increase is between the old lighthouse-keeper's garden and the summit of the Rock. We counted around 10,000 sites in this area compared with 6,500 five years ago."

Gannets are Britain's largest seabird, with a wing span of more than 6ft (1.8m), and can live for more than 30 years.

They have such good eyesight that they can spot schools of fish below the surface of the water and dive at speeds of up to 62mph (100kph).

Sarah Wanless, from CEH, said: "Our long-term research on North Sea seabirds aims to understand how species such as the gannet will cope with the rapid pace of environmental change. This is our fifth census of the Bass Rock in the last 30 years.

"It is particularly heartening to see them doing so well when so many other seabirds in Scotland appear to be in trouble; however, the Bass Rock is a small island and the gannets have now filled most of the available nesting habitat. The colony now has only very limited capacity for further increase."

The colony on St Kilda, 40 miles (64km) west of the Outer Hebrides, has stopped increasing and had 60,000 AOS at the last count in 2013.

Bonaventure Island had 59,000 at its peak in 2009 and has since decreased by around 20 per cent.