Swifts are among the most overlooked of birds, as they tend to fly fairly high above the ground (typically much higher than swallows) and they never land on branches, fences or other perches simply because their tiny, forward-facing toes do not allow this. As birds go, they are drably plumaged in shades of charcoal, umber and white so the majority of people are completely unaware of their presence.
Swifts are often confused with swallows although they are not related to them – both are aerial feeders, capturing small insects on the wing and they share many physical characteristics as a result of convergent evolution. The best way to tell these two groups apart is by the shape of the wings and the way they fly – swifts have narrow, sickle shaped wings and fly faster in wider arcs than swallows which have broader wings to glide and bank in a more relaxed manner. Swallows regularly perch on fences, branches and overhead wires, and many have bright blue backs and orange on the head.
The Alpine Swift is one of the largest and most impressive members of the family, arriving here as a migrant in August and departing around May. These white-bellied bombers frequent mountainous areas, building their clay nest between cracks in a vertical cliff. Here, their little feet are perfectly adapted to clinging onto the rock face. Several pairs usually nest close together in a colony of 20 or 3o and they forage together too. Depending upon weather conditions, flocks descend to lower elevations either because their mountain home is misted up or because warm weather has led to an emergence of abundant prey in flat country, above wetlands or along the seashore.
Watching these birds is always an incredible experience as they hurtle about at speeds well in excess of 100km per hour. I have had some memorable encounters along the Drakensberg escarpment with squadrons of these swifts scudding by at breakneck speed. Once or twice, I’ve been so close that I could feel the rush of air in their wake.
However, it was while having a tea break on our balcony, that this group of a dozen or so appeared out of the blue. I’m not sure if they nest on the nearby cliffs of Hoek-van-die-Berg or further afield, but I must take a hike up there to check. Swooping low above the houses and out towards the sea, they were not alone, as White-rumped Swift, Rock Martin and Greater Striped Swallow helped to hoover up minuscule winged insects. They put on a show for about fifteen minutes or so before disappearing as suddenly as they arrived.
As their name suggests, the Alpine Swift occurs in the Alps of Western Europe, but its range also extends east to the Himalayas and south to our tip of Africa.
Vermont, Hermanus, Western Cape, South Africa. October 2014.