Our house is within about 250 metres of the Hermanus coastal path and over the past several weeks, I have watched what I figure to be the same pair of Swift Terns in synchronized courtship flight. These supremely elegant birds fly together in dramatically beautiful tandem style – recalling olympic ice skaters as they carve lyrical shapes across the sky. Whether one or both members of the pair are calling, I cannot say, but I usually hear the croaky ‘kirrak, kirrak’ call first and only then see the snow-white birds skating across the sky. When I am able to get binoculars onto them, one tern (the male) can often be seen holding a fish in its bill – another element of courtship.
Earlier this week, I was astounded to see the pair in tandem at a tremendous height – mere ‘pin-pricks’ – which I estimated at at least 1000 metres above the sea, perhaps twice that! Even more remarkably, I have on several occasions heard the distinctive call at night – high above our house – indicating that this balletic courtship dance carries on after dark, often under a full moon.
Duncan Butchart, Hermanus, South Africa