Michael McCarthy: Spring is here when this pair are caught necking

Nature Notebook: They were shaking their heads, as if saying, Oh no no no. <I>Oh no no no</I>

Funny what you can see out of the corner of your eye. Shuffling over Hampton Court Bridge across the Thames on Saturday, bowed against the biting wind, and glancing at the water as I cannot prevent myself from doing when crossing any river anywhere, I glimpsed a couple of birds. Long-necked things. Pointy ears. They were great crested grebes.

I would have just registered them and shuffled on, but the second's glimpse revealed something else, visible instantly in their demeanour, in the way they seemed to be squaring up to each other. They were displaying. They were swimming towards each other and shaking their heads from side to side, each in turn, as if each were saying: Oh no no no. Oh no no no. Oh no no no.

This is the beginning of a mating dance, one of the most spectacular courting behaviours of any British bird, famously described by the young Julian Huxley in a 1914 scientific paper later published in hard covers. When the dance reaches its maximum intensity the birds swim right up to each other and entwine their necks, their splendidly-topped-with-chestnut-ear tufts necks, and sometimes they rear up out of their river or lake, treading water with their feet and pushing their white breasts together.

When, a century ago, the young evolutionary biologist Huxley began observing this on Tring reservoirs in Hertfordshire, Podiceps cristatus was a truly rare bird, one which had been driven almost to extinction by demand for its chestnut feathers to adorn women's hats. Nowadays it is thankfully abundant and can be seen on many sections of London's river, even right next to a bridge as traffic-clogged as Hampton Court, albeit if only briefly, on Saturday; for after a minute or so the birds disappeared, without performing a grebe Full Monty, alas. Yet in that glimpse out of the corner of my eye I had seen something more than the start of one of nature's great displays; I had seen incontrovertible evidence, with the arrival of courtship, that this teeth-gritting, shoulder-hunching, ice-slipping, scarf-necessitating cough-hacking interminable winter is ending at last.

Literary fame for the GCG

Beautiful as they come, the GCG, but am I alone in finding its name faintly comic? Evelyn Waugh made good use of it in Scoop when John Boot, the diffident rural writer who is mistakenly sent to cover the war in Ishmaelia – he of "feather-footed through the plashy fen passes the questing vole" – writes a piece for the Daily Beast about badger-hunting with terriers, and his young sister crosses out "badger" and substitutes "great crested grebe" all the way through. The cries of outrage resound through the shires.