Sound Escape 282. Immerse yourself in the manic action of a sand martin colony

As you crest a little riverside cliff, the air is filled with clicks, trills and buzzes. Squadrons of sand martins career wildly around you from their colony – a series of burrows dug into the sandy cliff face. The air is alive with aerobatic birds, including the first broods of this year's youngsters who are revelling in flight for the first time. BBC Countryfile Magazine's Plodcast Sound Escapes…