It is the time of the Hunters’ Moon, this week.
It will leap, white, into the night, and the ancient thrill in the central core of our primate past will quicken the pulse in some of us.
I was as close as I shall ever be here, in my photograph I took in the Hindu Kush years ago as the October moon rose above the mountains.
There was the howl of wolves, and the clash of ibex horns, and the passage of bar-headed geese from Tibet to the plains of India, above me.
But now it is Sussex, and civilisation. In these sombre woods, where black shadows and bright moon beams muddle the vision, there will be the guttural wild boar-like roar of the fallow bucks.
They pound the earth with their hooves, and challenge the echoes.
It is almost an ancient world again. I cannot usually see them, however quietly I creep through the forest in the darkness.
Of course I can see them in the parks. But that is tame day.
There will be the moon over the marshes too.
The midnight tide will be one of the biggest of the year.
At these times widgeon will often hurtle back and forth in the sky excited by the unexpected brilliance of the night.
What I always hope for is a thin sheet of alto cumulus clouds under the October moon.
This causes a circular rainbow around the moon as light coruscates through ice crystals.
These million prisms combine to split the light into a lovely circle of colour.
The rest of the cloud sheet is thin enough to become brilliant white, an almost dazzling backdrop to the teams of wild ducks sporting above the estuary.
The cock widgeon call with a continual chorus of excited whistles that can be heard half a mile away.
Several hundred can sometimes be seen over Chichester or Pagham harbours. Above the flood waters of Amberley Wildbrooks on these autumn or winter nights of bright moon, several thousand widgeon may provide an unforgettable kaleidoscope of changing shape and pattern.
Another moment the October moon will bring which I look forward to every year is the night-flight of redwings from Sweden.
If you go outside and the surroundings are quiet, you can often hear the faint call of these migrants, a soft lisping seep-seep, which is their call signal by which they stay together.
Sometimes I have, by staring at the moon through binoculars, seen them cross the globe either close by or distantly.
Hunters’ Moons are the peak times for bird migration into Britain and used to block out military radar screens making them useless for defence.
I once had a big surprise when far out on the Norfolk marshes under a Hunters’ Moon when it was eclipsed.
I had not been aware this was to happen. I was crossing some dangerous mudflats at the time when gradually all the light faded into a dark red glow like a dying ember.
Some clouds came up, too, and I was in almost complete darkness in that black sticky wilderness. Now that was real primeval fear.