By Jenny Pearson
Every summer, the sea around the Isle of Cumbrae attract numerous seabirds. Seabirds are a fascinating group of animals, in order to survive in the harsh sea environments, they have developed incredible adaptations that differentiate them from there terrestrial cousins. When the temperatures warm and they return to our coasts to breed and feed, we are provided with a fantastic opportunity to watch, admire, and learn about these incredible birds.
Unlike the birds in our garden, seabirds live long lives that span decades. They grow strong and fit, a necessity for a life at sea. They also indulge in fantastic parental care, usually dedicating their summers to rearing one chick at a time to ensure the best chances of survival for their little ones. Many of them rear their chick for many months, collecting food for the chick and neglecting their own nutritional requirements. Like all birds, they must reach maturity prior to mating and rearing chicks; but unlike terrestrial birds, sea birds take a long time to reach the required maturity levels. They spend their (often decade year long) childhoods getting strong and fit, and learning the seas, to ensure they are in fighting fit condition for the challenging breeding seasons ahead they will dedicate their adult years to.
We are fortunate to have many sea-bird species come to visit the coasts of the isle of Cumbrae each summer after spending many harsh winters at sea.
Gannets Morus bassanus
Northern Gannets are large, striking birds that live across the northern Atlantic Ocean, but two thirds of the worldwide gannet population spend their summers in the waters around the UK – our local population resides on Ailsa Craig, an uninhabited island in the Clyde Seas. Northern Gannets are a member of the Sulids family which contains 10 species that share similar behavioural and physical characteristics. Northern Gannets are the only member of this family that visits the shores of Britain.
Adult gannets have a brilliant white plumage, with ink black wing tips. On their head, their feathers are a soft orange. Juveniles have a black and white mottled plumage and can be aged by the stage of mottling they display.
Gannets are incredibly streamlined and fly beautifully across the water. They will travel long distances from their breeding colonies to feed – using their strong sense of smell and memory to navigate.
Gannets are plunge feeders – they rise up to a height of 40 meters, and dive down headfirst at an impressive speed of 100kmh! To do this, gannets must dive at a direct angle to prevent them from breaking their necks when they hit the water. The long, strong streamlined bill and body helps them break the water smoothly and special ability to lock together their vertebrae helps them protect their neck and spine while a third eye lid prevents damage to the eyes. On a quiet day by the coast, you might hear the woosh and gentle splash as they hit the water before you see them.
The Northern Penguin – the Auk Family
Auks are a family of seabirds that evolved in the Northern Atlantic. They are medium-sized seabirds that have evolved similar traits to the southern hemispheres most famous family of seabirds – penguins. This is called convergent evolution – where two different species evolve similar traits independently due to living in similar conditions and having similar challenges.
Like penguins, the auks are poor walkers. Their wings are short and (unlike penguins) can fly, but they fly with little efficiency and they never reach great hights. However, they are fantastic swimmers, and they use their wings to propel themselves through the water. They dive for food and some auks have been recorded diving as deep as 100m!
Auks gather in dense colonies on cliff edges and remote islands to breed – sometimes termed “sea bird cities”.
Off the coast of Cumbrae – we are regularly visited by three species of Auk – Razorbills, Guillemots and Black Guillemots.
Sandwich Tern Sterna sandvicensis
The sandwich tern makes sure to mark its return to our coast with a noisy and scratchy call from the sky. They spend their non-breeding winter seasons in the more tropical parts of the world but migrate to more temperate regions to spend their breeding seasons and take advantage of our productive seas.
Sandwich terns have been recorded across Atlantic coasts, around the Black Sea and the Caspian Sea, parts of the Indian Ocean, and on the Central America Pacific Coast.
There are around 40 tern species on the planet. To identify the Sandwich tern, look for long and heavy black bill with a distinctive yellow tip. It wears its head feathers in a shaggy crest when at rest but wears them sleek and tidy when in flight. They have a short, forked tail which helps to distinguish the Sandwich tern from similar gull species.
Long black bill with a yellow tip, graceful fliers, shaggy crest, neat when flying, short, forked tail, point their head down when feeding – distinctive
Manx Shearwaters Puffinus puffinus
Shearwaters are found in seas across the globe, but most often in the colder regions. Members of the petrel family, they are strong fliers and incredible migrators – Manx shearwaters will cover 20,000km each year, travelling between breeding sites in the North East Atlantic and non-breeding regions in the South West Atlantic.
Many Shearwaters come together in colonies to breed. They are ground nesters and so come to remote islands and cliff edges that will be free of ground predators that would threaten their nests. Rats and domestic cats can threaten populations and areas where rats have been accidentally introduced, Manx Shearwater populations have declined.
Manx Shearwaters take extra precautions to reduce their risk of being spotted by predators – they only enter their burrow in the night-time darkness. Similarly, to auks, Shearwaters are awkward on land, they stumble slowly as they walk, making them prime targets for predators. In order to find their burrows in the dark, Manx Shearwaters use their well-adapted eyesight, and their strong sense of smell and hearing.
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