What makes the Bass Rock for birds?
The plug of an ancient volcano, its shape makes an ideal breeding ground for the Northern Gannet (Morus bassanus).
The Bass Rock looms steeply out of the Firth of Forth, the last remnants of an ancient volcano that erupted around 330 million years ago. Magma trapped deeply beneath the volcano’s crater cooled slowly making a really tough igneous rock called phonolite. Over millions of years the overlying and surrounding less-resistant rock has gradually eroded, leaving today’s upstanding plug with vertical cliffs and a flat top.
The shape of the Bass Rock creates a range of suitable habitats for nesting seabirds. The flat top, protected from predators by its steep surrounding cliffs, is an ideal nesting site for gannets. And the surrounding sea means there’s a fishy buffet right on their doorstep.
Such is the attraction and affinity that it’s not only the largest gannet colony in the UK, but they are named after the Bass Rock (Morus bassanus). Around 150,000 birds return there each year to raise their young. It’s also a habitat for razorbills, shags and guillemots who nest on the cliffs, and seals that haul up on the rocks below. The Bass Rock is protected as a Site of Special Scientific Interest. Limited human activity on the island, protection from predators, and ideal nesting sites makes it a haven for birdlife.
Further out to sea the Isle of May, A National Nature Reserve and another island made of igneous rock, is home to an incredible variety of birds. Originally a flat sill of dolerite, it has later tilted, creating high vertical cliffs on its west side and low-lying rocky platforms to the east. The western cliffs are lined with crevices and ledges on which seabirds nest; the eastern side has rocks sloping to the shore. This geo-geometry has allowed soil to build creating grassy cliff edges that puffins can burrow in. Close to the sea, rock slabs make ideal winter pupping grounds for grey seals. The flat-lying rock extends to form a rocky tidal reef teeming with crustaceans, molluscs and other invertebrates which feed the varied bird colonies.
‘One of the 12 wildlife wonders of the world‘ David Attenborough
‘the calling of the solans [gannets], and the plash [splash] of the sea, and the rock echoes that hung continually in our ears. When the waves were anyway great they roared about the rock like thunder and the drums of armies, dreadful, but merry to hear, and it was in the calm days when a man could daunt himself with listening; so many still, hollow noises haunted and reverberated in the porches of the rock.‘ Robert Louis Stevenson, Catriona
Image: the Bass Rock
by Drift cafe www.driftalong.co.uk
The Scottish Seabird Centre webcams allow you to watch the birds and other wildlife throughout the year