Eight ten a.m. September 13, 2006 will I hope live long in my memory.

For at that moment my flagging mid-life mind was once again rejuvenated, by migrant lifeblood energy which might ensure vital continuity for this beleaguered planet. Personal rejuvenation of a kind at once familiar yet always utterly unique. Heading north out of Arusha on the Nairobi road we were rounding the broad western shoulder of Meru Volcano en route the squalid Maasai village of Oldonyo Sambu and that slice of peace beyond: the serenity of Angyata Osugat – a treeless plain of dust.

Suddenly, as we passed a scar beside the road where erosion from a million cattle hooves, on their daily trek for water, has cut a swathe one hundred metres broad through the parched and riddled grassland, I shouted to Dismas “Stop!!”

Then, as a more modified Anglo-Saxon burst up from my gullet I queried “a Wheatear?”

Ten seconds upon reflection the bird guide-trainer, late twentieth century right-brain qualifier pronounced: “a Northern Wheatear”.

Dismas braked well and pulled over to the nearest semi-soft shoulder of the narrow road and I scrambled down from the Land Rover. Such was the incipient moonscape there that I had to walk back, through a profuse and ginger talcum, fully two hundred metres to the bleached and tussocky ‘sward’ wherein my white-arsed chat was lurking.

Now I had spied a female from the car, yet here before me a splendid male in pristine ‘winter dress’ was all a bobbing and a flirting. Wow! What a beauty! Each crisply margined feather fresh was simply a revelation to my by now worn and ragged Afrotropic brain. The magic face on that bird; wherein the brightest eye drop shines back at you from a neatly blackened bandit mask of tiny feathers stretched across ears and lores. Offset by a sharp and creamy supercilium, soft white chin and richly warm buff throat, breast and vent separated by a pure white belly. A grey brown back, distinctly long dark wings and long square tail, each flight feather edged with either tawny gold or cream; and when he flew the famous bouncing rump and upper tail of snowy white wrapped around the inverted T, hallmark of his congeners; that perhaps provided the Oenanthe name supposedly first coined by Aristotle.

Sharp black bill and long black legs (as well as wings and tail) were all in action as he parried the assaults of three Capped Wheatears who were firmly established on this apparently very desirable patch of roadside dirt. Then the female reappeared amongst a fidgety and motley group of Grassland Pipits and Red-capped Larks foraging in the verge just across the road. For twenty minutes I tracked them, male and female both, back and fore all the while praying that neither would be smashed down by some erratic speeding truck.

With a Maasai Camel Camp to check and bird tour routes to recce, all too soon we were forced to push on, driving the long gravel road to the hillside village of Ngare Nanyuki. On our return journey at about midday, under a thankfully overcast sky, just outside that sprawling village we stopped to allow a large herd of goats to pass. There I spotted a second splendid male Oenanthe nipping up a bare and rocky hillside to perch on a grey lichen encrusted boulder.

We got out and were fortunate to be able to scope this individual for many minutes as he sat and diligently preened upon a particularly large and finely decked stone. Once again I was struck by the total perfection of his appearance. Though on this occasion as much by athletic proportions of wing and leg and tail as by that freshly minted plumage.

My analytic mind was tempted by these protracted close-up views to consider the provenance of such truly remarkable birds. I remembered reading somewhere that Tanzanian wintering Northern Wheatears are thought to hail from the farthest eastern reaches of the range of nominate Oenanthe oenanthe. From north slope Alaska and the western edge of the Mackenzie delta in Canadian north west territory.

So those admirable long and pointed wings, and sturdy projecting tail, on these marvellous beings are powered by flight muscles that have burned perhaps fifteen grams of fat, largely derived from flies, over the past two gargantuan weeks of globe arching travel. Fifteen centimetres long, small birds yet burning so brightly, a purity of life force almost unimaginable to this earth-bound twenty first century misfit man. They are perfectly built indeed. Selected to sustain a truly epic great circle flight of over twelve thousand kilometres: across a melting Arctic Ocean, via tundras of northernmost Siberia, through desert barrens of Central Asia, the Hindu Kush, over the Arabian Sea, passing the rugged Horn of Africa and down the Swahili coast to arrive today in front of a tiny yet very receptive audience beside the sleeping giants of Meru and Kilimanjaro. Giants who have watched them come and go these past two million years as their ancestors followed the retreating ice caps, through the vicissitudes of climate change, to the farthest corners of the northern world - and back.