A wildlife group is asking people to look out for four familiar birds with an international lifestyle.
Over the next six weeks swallows, swifts, sand martins and house martins will return to the UK.
They have spent the winter in Africa, but are returning home for the summer, before returning south again in the autumn.
Sand martins are usually the first to arrive and should be here soon, followed in the middle of next month by swallows and house martins. Swifts should arrive in late April or early May.
Recent years have seen declines in the number of such birds, especially the swift.
The reasons are only partially understood, but it is thought suitable nesting sites are becoming scarcer.
The Biodiversity Partnership wants to raise awareness of the birds, and develop a better understanding of their distribution.
Supported by Scottish Natural Heritage, it is running an online survey.
Postcards will also be available from libraries and community centres, and council and SNH offices.
Space is given to record the date and location of people’s first sighting for each bird.
