Swallows fly from southern Africa for the British summer

The first of the migratory birds arrived at the Vane Farm Nature Reserve, Perth and Kinross, on Tuesday, a day earlier than last year.

The Royal Society for the Protection of Birds (RSPB) Scotland said the early sightings of birds such as swallows and housemartins were signs of global warming.

Four months ago a little egret arrived at the reserve by Loch Leven, raising hopes that the species could breed for the first time in Scotland this year.

Coming of summer

However, the RSPB cautioned that warmer summers and reduced snowfall could spell the end for established native birds such as the dotterel, ptarmigan and snow bunting.

Vane Farm warden Dave Jones said: "As the old adage goes, one swallow does not make a summer. However, it is a sure sign of the coming of summer and we're seeing it earlier and earlier.

"The warm weather has encouraged a host of summer visitors to come early. This is the earliest in the year we can ever remember having swallows at Vane Farm.

"Housemartins seem attracted by the warmer temperatures and have been seen at the reserve since Tuesday. Last year they didn't arrive until the end of April.

"While the issue of climate change remains a hot topic, the change in migratory patterns does seem to delight many birdwatchers."

RSPB Scotland's conservation policy officer Clifton Bain added: "We do of course enjoy our early swallows, but the overall effects of climate change for wildlife are far more sinister.