Nature Studies by Michael McCarthy: A rare glimpse of the glorious woodcock

Sometimes you only get a glimpse, but a glimpse is enough. A week last Tuesday, I was tramping across a Surrey heathland, a place that was but 15 minutes in the car from Guildford but looked so wild, with its dark heather plains and its pine-clad and birch-clad horizons, that it could have been Russia. In fact, it has represented Russia in movies more than once. Surrey continues to amaze. You think it's all London suburbs. Half of it is wilderness. It's the county most taken for granted.

I was looking for a very special bird, and failed to see it; I'll write about it if I do. But in the middle of the tramp across the heath there was a sudden detonation from the bracken 10 yards in front and what appeared to be a plump, brown football shot away like an artillery shell fired from within the ferns, straight and true and fizzingly fast, until it reached the pinewoods and disappeared. The incident was over in well under 10 seconds.

It was another special creature: a woodcock. The brief glimpse of its disappearing back is all you're likely to see at this time of the year, as it has a good claim to be Britain's most mysterious, cryptic, least visible bird. It's a long-billed wader, but it doesn't do what other waders do, which is live and feed along shorelines (Americans call waders "shorebirds"). It lives in woodlands, in the thick bushy under-storey of brambles and coppice and scrub. And it operates at night, along with the owls and the ghosts, coming out of the woods onto adjoining fields where it spends the dark hours probing the ground with its bill, for earthworms.

In this – although I've never seen the comparison made – it reminds me of nothing so much as New Zealand's flightless national bird, the kiwi, which, because there were no mammals in that country (apart from a single bat species), evolved to occupy something like the ecological niche of our badger, for a nocturnal worm-eater. The badger-bird. There is striking film of long-billed kiwis hunting at night, taken with infra-red light so the stars in the background look like blazing matches, which is absolutely gripping. I'm sure such an infra-red image of woodcock feeding in a field, just like woodpigeons except that everything is pitch black, would be enthralling too. But I've never seen it.

They are birds you hardly ever get to see properly, even in daylight, because their camouflage is perfect for the woodland floor, where in the daytime they lie up in perfect stillness for hours; no bird is better at blending in. And, as I know from once having come across and handled a dead woodcock, the varied russets and browns of the plumage, seen close up, are in fact exquisitely lovely.

But in so far as you can catch a casual glimpse of the live bird, now is the time, because in autumn the woodcock which breed in Britain, and may number anything from under 10,000 to nearly 80,000 pairs (they're so skulking that they're immensely hard to count accurately) are joined by a colossal influx of birds from Scandinavia and Russia, looking for unfrozen winter quarters.

These may number as many as 800,000. They fly over the North Sea in the dark, arriving from late October, especially around November's full moon, which gamekeepers call "the woodcock moon". This week the RSPB put out an unusual press release warning people not to be alarmed by plump, long-billed birds flying into their windows at night; these were merely migrating woodcock (the RSPB said it was getting calls every day).

Yet although the winter woodcock continue to flood in, something appears to be going seriously wrong with our summer birds, the ones which breed here. The fieldwork for the new Atlas of Breeding Birds being prepared by the British Trust for Ornithology (for publication in 2013) has turned up an enormous shrinkage in the bird's range since the last atlas was done, 20 years ago, of no less than 44 per cent. Nearly half of the places where they were found breeding in Britain in 1990 have no woodcock now.

What on earth is happening? Are they being affected by deer over-grazing the woodlands, which is leading to the disappearance of nightingales and other woodland species needing scrub to nest in? Are they being affected by hunting pressure? Woodcock are a prime species in game shooting (in France they are known as la reine des gibiers, or "the queen of game birds") and although they can legally be shot only in the winter, British breeding birds, which generally do not migrate, are just as likely to be shot as the more numerous Russian winter visitors.

Nobody knows the answer. But to me, the fact that our own breeding birds seem to be disappearing makes the sight of any woodcock even more of an event. Any sighting of the long-billed bird of the night is to be valued; even a glimpse of one belting away is enough to make the day memorable.

The spinier the case, the better the nut

Several canny readers have emailed me about last week's subject of sweet chestnuts, which, I said, were small and fiddly if they came from British trees (as opposed to plump ones from trees in France and Italy). The general consensus: that is true to a degree but, I was told, you are not trying hard enough. There are plump British chestnuts, if you know where to find them. Another suggestion: the spinier the case, the better the nut.

m.mccarthy@independent.co.uk