For many of us who enjoy walking and climbing in the Scottish Highliands, much of the pleasure gained from a long day on the hills comes not just from attaining the goal of reaching the summit(s), but also from the wildlife that may be encountered along the way. The sight of a Golden Eagle Aquila chrysaetos soaring over a distant ridge or the eerie call of a Black-throated Diver Gavia arctica on a remote loch may add just that extra vital ingredient that makes for a 'perfect day'.