Amazed by wonders of migration
THERE is surely nothing more exciting than witnessing the annual migration of thousands of birds, fish and animals, large and small, familiar and unrecognised.
Somehow, from somewhere, out of the blue, over the sea, down from the sky and across land they come, making their way against the odds that would appal any human, crossing seas and countries in the darkness of the night, and yet arriving, as often as not, at the same place they left the previous autumn.
Who has not thrilled to Sir David Attenborough’s wonderful films of the awesome numbers of wildebeest braving crocodile attacks in the Mara River as they migrate annually from the Serengeti National Park in Tanzania to the greener pastures of the Maasai Mara National Reserve in Kenya during July through to October? It is Africa’s most incredible spectacle and often referred to as the ‘World Cup of Wildlife’.
Although Argyll cannot produce such dramatic hoofed sights these days, there are still some seasonal arrivals and departures that take the breath away.
A few decades ago in early spring, salmon and sea trout used to migrate upstream to spawn in their thousands. Not so very long ago, I stood in the darkness on the banks of the upper reaches of the River Ailort between Arieniskill and Loch Eilt on a spring tide, hearing them battling their way over the rapids and through the shallow water making a noise which was almost deafening as they moved forward en masse into the loch.
But for a few grizzly bears, bald sea eagles and wolves, one might have been in Alaska along with the Chinook and sockeye salmon.
And so it used to be at the mouth of the rivers Aline, Shiel, Moidart, Barr, White Glen, Kinlochteacuis, Coinnich (Kingairloch) Gour, Cona, Awe, the Scaddle and just about every other river on the west coast. There was no need for the dubious catch-and-release scheme then.
Today the fish have virtually disappeared and the emptiness is palpable. Where have the salmon and sea trout gone? What has happened? Anyone who solved this puzzle would become a millionaire overnight.
Another extraordinary sight is the migration of tiny common eels (Anguilla vulgaris) from their breeding grounds off the West Indies to the freshwater rivers and lochs of the British Isles. Their life story is one of the strangest in the natural history world. There are two sorts: yellow eels and silver eels. Young eels, or elvers, move up river in spring and large eels return in the autumn.
Until recently, nothing was known of their breeding grounds or their migration. By climbing onto each other’s backs, elvers can scale high waterfalls. They will also travel for quite long distances overland, wriggling across fields and through damp grass until they find their way into rivers and lochans where they may remain for 10 years and more. To enable them to journey in this miraculous way, they have several gill slits, each with a cavity that can be closed with a membrane so they can carry sufficient moisture with them as they travel.
In the history of evolution, which is the story of the great race of life through the ages, there are some fish who gradually left the sea for a life on the seashore and became half aquatic and half land-living animals.
Millions of years ago, these amphibious creatures found homes further inland and eventually abandoned the water altogether.
They were the forefathers of today’s seals and became extinct, while those that remained by the coast found they were in less danger and, learning to swim, hunted for food offshore. They lived entirely in the water, except for briefs spells on land when the sun was warm, and during the breeding season. Generally, there are two types of seals found around Argyll’s coastline - the grey seal, of which there are literally thousands, and the common seal, which is not quite so plentiful as its name suggests. During the autumn, when the equinoctial gales send the great Atlantic rollers crashing against the rocky cliffs of the west, grey seal bulls fight with one another for their mates. One male, if he is large enough, will collect a whole harem and guard it against all-comers. Males can be nine feet long and often weigh up to 55 stone.
Seals migrate to traditional calving grounds in October and what a spectacle they make, coming in to have their pups. I have watched grey seals calving on Soa Island off Iona and Fladda and Cairnaburg Mor in the Treshnish Isles. Here there are sheltered bays and sandy beaches, allowing the heavily pregnant cows to heave themselves out of the water and upwards, sometimes 50 feet beyond the high-water mark, to produce young among bracken-covered boulders.
When the pups are born and licked clean by their mothers, they are almost pure white and the picture of innocence. But beware: they have strong jaws and teeth as sharp as razors.
Woe betide any man or beast who comes between mother and child.