In this article, RSPB Scotland’s species officer for Uist, Stuart Taylor, considers the fortunes of that classic bird of summer, the swallow, and its relatives, the sand martin and house martin
The old saying states that, “one swallow doesn’t make a summer”. Does that mean that years ago summer never actually arrived in the Western Isles as swallows and their relatives were not as numerous here as they are today?
Local birdwatchers often comment on how the numbers of swallows and sand martins are slowly increasing on the Western Isles as well as one or two other species.
These comments caused me to look into past records to see what changes were taking place in their populations.
Most people recognise the swallow as it swoops around chasing flying insects and twittering to each other when they meet up.
Until the 1990’s there was only the occasional breeding record but now almost every township has a pair or two of this familiar bird.
They will build a nest of mud and grass on a beam in a byre and rear two or sometimes three broods of young in a season.
They will use the same nest in successive years and it is important that if a nest is found in a byre, or barn, that a door or window be left open to allow the adults to come and feed their young. Each year seems to see another building being occupied.
They arrive on the islands in April and stay until September when they return to their wintering grounds in Africa.
Less familiar will be the sand martin, another aerial feeder which as the name implies, likes to breed in holes in sand dunes and banks.
It has brown upperparts and is white underneath but with a brown band across the breast, and also spends the winter in Africa.
Unlike the swallow though, there was a time when it was more numerous both on the Western Isles and much of Britain.
However, a very dry season occurred in 1984 and many hundreds of birds died as they struggled to get across the Sahara Desert on their migration.
Sand martins were unknown as breeding birds in the Western Isles until 2010 when ten pairs were found breeding in sand dunes in the Drimsdale, on South Uist.
Since then, numbers have slowly crept up and small colonies can sometimes be found in steep, sandy banks. Under normal circumstances this little bird can live for up to eight years.
Closely related to the sand martin is the house martin, a very familiar birds in most parts of the British Isles, due to their habit of creating mud-built nests under the eaves of buildings.
Breeding attempts on the Western Isles have been few and far between with the last nest being found on North Uist in 2003.
However as only one bird was present, nothing came of this. Maybe they will increase in the future too.
Other birds are becoming more numerous these days and recent years have seen increases in species such as the linnet, chaffinch and goldfinch.
These three birds are seed eaters for much of the year, but the latter two species need insects and caterpillars on which to feed their young.
Why are these birds making welcome increases on the Western Isles?
Is it global warming/climate change? It is known that in Southern England, warmer, wetter summers are encouraging more insects to emerge, and birds such as herons and Dartford warblers for example are spreading and following their food as it creeps slowly northwards.
This is all very exciting stuff but sadly it means that creatures that live further North in the Arctic Circle, are declining rapidly. Will polar bears and walruses become extinct in our own life times?
What will be the next new species to make its home on the Western Isles? Are more swallows on the way?