Lindisfarne is set to welcome back its winter guests

We await many times that number, for tens of thousands of geese overwinter at Lindisfarne National Nature Reserve each year.

Anticipation fills the Reserve, which will be transformed by their presence.

I am away when the first of them arrive, receive a video message – ‘The Pinks are here!’

Though tinny over my phone speaker, their clamour is unmistakable. Days later, we rush out to the yard to glimpse a small skein headed south west. Lying in my bed at night, I hear a high-above honking, thrill at the sound.

To reach Northumberland, geese must travel for thousands of miles – the pink-footed from Iceland, the light-bellied brent from Svalbard – halfway between Norway and the North Pole.

How many wingbeats to a mile, I wonder? They navigate using the positions of sun and stars, wave direction, visual landmarks – even the Earth’s magnetic field, although scientists have long puzzled over how this might be possible.

This year, two teams of academics studying the problem concluded that a key cryptochrome protein in birds’ eyes allow them to visualise magnetic fields. This replaces an earlier theory that navigation by magnetoreception was made possible by iron-rich cells in birds’ beaks.

Theories continue to develop – but none are quite so unusual as the 12th century (perhaps even earlier) explanation for the appearance of Barnacle geese in autumn.

Nobody had ever seen a barnacle goose hatch an egg – so where had they come from?

Peculiar enough: they had hatched from barnacles, grown from trees.

A ‘mysterious and remarkable generation’, related King Henry II’s chaplain Giraldus Cambrensis, adding ‘bishops and religious men eat them without sin during a fasting time, regarding them as not being flesh’. And here, perhaps, is a partial explanation for the belief – an excuse to eat barnacle, and the similar brent, geese and sidestep religious dietary restrictions.

How much people really believed the birds were ‘more fish than fowl’ may be up for debate, but the practice was widespread enough for Pope Innocent III to explicitly prohibit the eating of these geese during Lent.

An early conservation measure, perhaps, though intended to protect Christian souls rather than the geese themselves.

It was the conservation of geese and other wildfowl that formed the impetus for Lindisfarne’s designation in 1964 as a National Nature Reserve.

It is an internationally important site for geese, who have made the long annual pilgrimage to and from the Reserve for thousands of years.

We shall welcome once again the grey geese – greylag, bean, pink-footed and white-fronted.

These so-called grey geese are large, brownish and – at least to my untrained eye – hard to tell apart. A field guide is a help. The white-fronted has a white patch at the base of its bill; the bulky greylag has a large head and pale orange bill; the bean has a long neck and legs and long narrow bill; and the pink-footed – as well as the obvious – continues the rose-tinted theme with a pinkish plumage and short pink and black bill.

More distinctive are the smaller black geese – the barnacle and the brent. These geese are both amber list species, protected by law from harm. The barnacle is a pretty goose with a smart black hood, white face, patterned blue-grey wings and silvery white belly.

The brent is very small – indeed, not much bigger than a large duck – with a slim white, almost ecclesiastical, collar, and a black head and neck. Its two subspecies, the dark and light-bellied, have slate grey and silvery underparts respectively – contrasting to a lesser or greater degree with its dark wing.

As for identifying by sound, any attempt currently defies me, though my newly-acquired Poyser reference book informs me that the whitefront makes mostly a musical ‘lyo-lyok’, the greylag a raucous ‘aahng-aahng-aahng’ and the barnacle goose a harsh ‘gnuk’ (elsewhere described tome as resembling the yapping of small dogs).

The answer, I suppose, is to listen – and for this there will be ample opportunity over the coming months.

Once they arrive, exhausted by their long journeys, the geese seek the sanctuary of quiet places where they may rest, feed and replenish their strength. They are large birds, and their mainly herbivorous diet means they must feed for much of the day to meet their energy requirements.

Long necks bowing and lifting, they seem to converse as they feed – the latest gossip perhaps, with an occasional appalled squawk. In the saltmarsh, bustling brent geese feed on the ribbon-like Zostera leaves – seagrass meadows on the Reserve draw half of the world’s small population of light-bellied Brent to overwinter here.

Nearby, the grey geese and barnacle geese graze in their gaggles in grassland and stewarded farmland. It is vital that these wearied wanderers are allowed this time undisturbed by humans or dogs. If forced to take flight on diminishing energy, and unable to feed sufficiently to refuel, they will starve.

It is another peril for creatures which have already endured much.

After feeding during the diminishing daylight hours, the geese will return to roosting spots where they will congregate in their thousands. Last year’s peak counts saw 9,500 pink-footed, 16,750 barnacle and 4,000 light-bellied brent, but numbers cannot come near to evoking the awe in witnessing this assembly.

In estuaries, they stand on mudflats, settling on water as the tide rises – safer here from humans and other predators.

At dawn, they leave the roost to feed. As they rise in their hundreds and thousands it seems for a moment that they will blot out the skies completely, yet it is their cacophony of sound that astonishes most. We will watch from the white railings at Budle Bay – binoculars lifted, then lowered, for this spectacle needs only the naked eye.

For now, we wait – eyes trained upwards for their characteristic formations.

They spin skeins like messages across the skies – a succession of ragged Vs and Ws; untranslatable and lacking vowels. Perhaps it spells autumn.

The geese are coming.

CERIS ASTON is an apprentice at Lindisfarne National Nature Reserve and author of thewordsandthebees.blog. You can follow her on Twitter @insocrates