Less than 200 years ago, you could have heard corncrakes calling in nearby fields while you stood in the middle of Edinburgh. Not any more: this medium-sized game-bird has been one of the major casualties of modern agricultural change. But islands in the Hebrides are still a corncrake stronghold.
What to look for
First of all, use your ears. The repetitive, rasping call of the corncrake (like running a piece of wood up and down a large comb) can go on all night (as some sleep-deprived Hebridean crofters may tell you). Try to home-in on the call source by looking for a hen-sized bird poking its head up from surrounding plants.
The retreat and decline of the corncrake across Europe is linked to the huge loss of hay meadows and to mechanisation of grass cutting for silage. Earlier cutting for silage with faster mowers, working from the edge of a field inwards, has been the death of many corncrake broods. Later cutting, from the centre working outwards, allows young corncrakes to escape. One reason the islands of western Scotland are a European corncrake stronghold is that agriculture has been less intensive there in recent decades.
When and where to see
Corncrakes migrate to Africa in late summer and don't return until early the next summer. So both bird and call are (largely) an experience for the months of May, June and July in Scotland. Hotspots are Tiree, Coll, the Uists and Benbecula.
For more information see the RSPB's corncrake page.