29 August, 2013
Many of our properties provide a summer home for migrating birds. In late August, as daylight hours decline, they set off for their winter homes.
Ornithologists do not know exactly what triggers migration. It could be length of day or dwindling food supply, or perhaps genetic memory. But as autumn draws in, we can be sure they will depart.
It was only relatively recently that we learned where birds migrate to. This was initially achieved by ringing – attaching a metal band to a bird’s ankle. However this was not easy. Over 150,000 house martins were ringed before one was finally recovered in Nigeria in 1985.
Modern technology allows much easier recording of bird migration. Tiny radio transmitters allow scientists to follow individual birds on their journeys. The RSPB are currently tracking osprey nestlings from Loch Garten, called Breagh and Oighrig, on their way to Africa. Their progress can be followed on the RSPB website .
Inchmahome Priory and Threave Castle, both surrounded by water, are excellent places to see ospreys in the summer. Their migration can be unpredictable. Last year, an osprey called Caledonia was tracked by the RSPB. She failed to complete the trip, and has been living near Seville, south-west Spain, for nearly a year.
Swallows and house martins nest at many Historic Scotland sites. Summer visitors to Caerlaverock, Corgarff or Aberdour Castles can watch these agile fliers skimming the ground and water to catch insects.
The first swallows leave in late July; the last in late September. They fly to South Africa, a round trip of 10,000 miles. This is extraordinary enough, but up until the late 1700s, it was believed that swallows hibernated in the mud at the bottom of ponds.
The puffin is another migrating species found at several HS sites, such as Inchcolm Abbey in the Firth of Forth, Sumburgh Head near Jarlshof, Shetland and the Brough of Birsay on Orkney. Having raised their broods, the puffins have now left. They will spend the winter at sea, most likely around the Bay of Biscay.
Another seabird often seen at coastal sites is the tern, often called the sea swallow because of its forked tail. The Arctic tern has one of the longest migrations of any bird, travelling all the way from the Northern Isles to the Antarctic Ocean. One tern which had been ringed was recorded as living to 26 years old. It must have flown about half a million miles during a lifetime of pole to pole migration.
One other migrating bird worth mentioning is the corncrake, which can still be seen – or more likely heard –on Iona. In Three Men in a Boat, Jerome K. Jerome refers to ‘the harsh croak of the corncrake’. This noisy bird was once common, but no longer. Those few which survive in Scotland will be well on their way to southern central Africa.
Incidentally, Iona is the only Historic Scotland site where I have heard a cuckoo. The cuckoo was, however, on Mull. It must have been a loud cuckoo.
Cuckoo, cuckoo, how do you?
In April I open my bill;
In May I sing by night and day;
In June I change my tune;
In July away I fly;
In August away I must.’