Nature Studies: How can a bird that weighs six grams get here from Denmark?

It used to be thought that goldcrests hitched a ride on woodcock – now we know they do it by themselves

The tiny goldcrest was once thought to piggyback on woodcock to cross the North Sea getty (Gety)

If you love the natural world, one of the most exciting places in Britain is the north Norfolk coast in autumn, especially with a North-east wind blowing, because its airflow brings a wonderful procession of migrant birds escaping the colder weather in continental Europe.

Last week there was such a nor-easter; in fact, the wind lines on the weather map seemed to point direct from Denmark, over the North Sea to Burnham Overy Staithe, the little harbour in the marshes where I found myself with my friend Paul Stancliffe from the British Trust for Ornithology, with high hopes of seeing birds that were out of the ordinary.

The omens were good. That day, snow had fallen in Germany and Belgium and the day before, the first wild swan of the autumn, a Bewick’s swan from Russia, had arrived at the Slimbridge wetland centre in Gloucestershire, the earliest such arrival for half a century. (The other reason I felt confident was the presence of Paul, who has the best birding skills of anyone I have ever met.)

And in fact, we started to see fascinating species as soon as we set out along the sea wall to Burnham Overy dunes, two miles away: flocks of fast-flying golden plovers and lumbering brent geese, while in the distance was a flock of about a thousand pink-footed geese, newly arrived from Iceland and just starting to build up their numbers.

The song birds were even more in evidence: dozens of blackbirds and robins (which you might think are commonplace, but these were blackbirds and robins which had just crossed the North Sea) and, especially, flocks of the other winter thrushes which come to us from Scandinavia, the redwings and the fieldfares. And there was a terrific rarity, on a fence at the edge of the dunes: a great grey shrike, a striking mini-predator in a splendid colour scheme of grey, black and white.

It was in the dunes that we saw the first goldcrest: Paul spotted it, a tiny bundle of exhaustion. For goldcrests, among our prettiest birds, are also Britain’s smallest, smaller than a man’s thumb and weighing about six grams, or a fifth of an ounce – that is, the weight of a 20p piece. How on earth can such a diminutive being fly across the North Sea? This seems so improbable that goldcrests were once known as “woodcock pilots” because it was believed they hitched a ride on the backs of migrating woodcock, the woodland waders which are many times their size. But now we know that, remarkably, they do it by themselves, and when they arrive, of course, they are desperate to feed.

We started to see more of them, frenziedly hunting for insects along the base of the sea wall: and for once we were above them, which meant that their lustrous golden crests were exquisitely visible, catching the sunlight. On a single bush we saw seven; but that was nothing to what we encountered when we moved on to Holkham Pines, a shelter belt of conifers on the sand dunes, a couple of miles to the east. The trees were crawling with goldcrests: I have never seen anything like it.

One bird was so intent of feeding that I approached it until it was four feet away from my face, and it began hovering like a hummingbird, trying to glean the minute insects from the underside of leaves, ignoring me completely. Many of the trees held up to a dozen of them at any one time, and it was a delight beyond measure to see so many, at such close quarters – for me, this is a bird that is usually a dot in the top of a fir tree.

Thanks to Paul’s amazing skills, we saw 63 bird species that day – my highest ever daily total.

The goldcrest invasion will stay in my memory. It felt like nature’s version of the Jewel House in the Tower of London: everywhere we went, we were surrounded by gems – but these were not only sparkling, they were full of life.