Gazing at Gannets
This spring around 150,000 Northern Gannets return to the Bass Rock in the Firth of Forth, the island which is responsible for their scientific name Morus bassanus. Whilst most of us feel we “know” about gannets often we don’t appreciate quite how impressive they are, after all common seabirds are always seen as a bit less interesting than their imperious cousins, the birds of prey.
The gannet is, in many ways, the king of the seabirds. It’s large stature, golden head and striking plumage all lend themselves to the role but it is under the skin where the real achievements lay.
A gannet will dive into the sea at a speed of around 60mph. To put that in perspective, that is the speed a human would hit the water if they dived off the Forth Road bridge. A human would not survive this and yet a much smaller animal with much weaker bones is able to do this activity several times a day for over 30 years without so much as a headache, pretty impressive really.
Their secret lays in what is best described as internal air bags. Small air sacs inflate in the gannets neck and head to absorb the shock of the impact whilst a special opaque membrane drops down over the gannets eyes to prevent any debris getting in during a dive. This membrane leads to the popular myth that gannets go blind from diving too often. This is completely untrue, gannets are simply superbly well adapted to life at sea. The gannet has even evolved internal nostrils to prevent water going up its nose during a dive!
Beneath the waves the gannets are every bit as sharp as in the skies. They can swim to a depth of 20 metres and hold their breath for almost a minute in order to give them time to hunt for fish. On many occasions the gannets dive deep down into the sea and catch fish on their return to the surface rather than attempting to catch fish on their initial plunging dive. Gannets often hunt in groups which creates problems as with many birds in the water and many more diving in at speed there is a risk of collisions, often resulting in fatal injuries.
Whilst graceful in the skies and in the seas the gannets are clumsy on land, often crash landing when returning to their cliff top nests. Gannets mate for life and, as they only lay one egg per year, are fiercely protective parents. Despite their seemingly caring nature a gannet will happily eat the chick of neighbour if it were left unattended. For this reason, space permitting, you will only find two gannet nests in every 10 square feet, as this allows every nest to be just out of pecking range of the next.
Many people ask why gannets choose to nest on exposed cliff edges, in the face of the elements. It certainly looks very high and exposed. However height and exposure are exactly what they look for as incoming wind hits the sheer rock face and is buffeted upwards which helps the lift the gannets into the air when they take off. This is particularly important for fledging chicks whose wings are weak, often resulting in a perilous and ungainly first flight into the waves below. Despite the difficulties, 9 out of 10 gannet chicks successfully leave the nest which results in gannet populations showing a small increase in numbers year on year.
The gannet is currently has “amber” status on the Birds of Conservation Concern list which means it is not yet endangered but that it could become endangered if its population decreases further. This is the reason why many object to the proposed wind farm development in the Firth of Forth, for fear it will reduce the gannet population to dangerously low levels.
What will happen to the gannets in the future is unclear but at the moment they remain a source of wonderment and a bit of an enigma, caring yet vicious, agile but clumsy. For now lets just admire their elegance and grace, whilst safely out of pecking range of course.
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