I've been waiting for this moment with more keenness than I could ever have imagined feeling a few years ago - the Swifts are here. They're back! Over London. Now it really feels like Summer is little more than a few minutes away.

On my long meander home from work this evening, I suddenly found myself under a rolling, boiling cloud of them freewheeling near the Serpentine. Just like a gang of cats in a net bag, they were careering in all directions; feinting, tumbling, soaring, biting, and snapping at what must be a mist of aerial plankton too fine for us on the ground ever to see.

Their rubber duck  soprano squeak of a call means there's another citizen of the air about. With those squeals, shrieks and swoons, they could be characters out of a steamy bodice ripper. It's drama, it's extravagance, it's passion, it's operatic.

Of the four acrobats who dominate the skies of summer, they are the last to arrive: Sand Martins are always the metaphorical early birds, next comes the Swallow, followed by House Martins, and then cannoning across the stage, the final act, which is for me always the most rousing and dramatic - enter the Swifts. Unforgettable. How mercury skits so wildly across water mirrors to a tee the excitement of the swifts scorching across the sky. Now if they could only leave a vapour trail...

And the sky is their true home; everything happens there, eating, sleeping, mating; the only thing that happens on terra firma is egg laying. Add incredible to unforgettable; these birds are truly amazing.

 I've been reading the daily reports in the London Bird wiki on the returning migrants; every day, something new, something closer to where I live. This is the bird I've been waiting for. I am ecstatic. Summer est arrive, or as near as damn it.