It sits at my feet, a marvel of fragility and camouflage. Just over an inch long and carefully mottled in greys and black on a faintly bluish background. “We found it yesterday,” says Karen, the RSPB volunteer, “Right where people from the holiday camp walk.”

Overhead a bird flits, as if yanked by a child on an invisible string, a thin sickle of white with a bright yellow bill. The egg at my feet may belong to that bird, a Little Tern, so we move away. “There’s about 40 nests,” says Karen, “From which we normally expect three chicks to survive.”

We are at Kessingland Ness on the first day of our marathon 500 mile walk from Lowestoft to Tilbury, a route that covers much of the Suffolk and Essex coastline. In my life so far the East Coast of England south of the Humber has rarely featured. More than half a century ago my parents took me to the Lincolnshire coast and on the first day of the summer holiday I ran on to the beach and stood on broken glass. My Dad gave me a Mars bar and dug the shards out with a penknife, but the damage was done. I know every cove and beach in the South-West and Wales. I can direct you to the best dinosaur footprints of North Yorkshire’s coast and give detailed advice on the islands of Scotland. Between Lowestoft and Tilbury, however, I am utterly lost. My mental map is bare. When I bought the OS maps for this walk I was shocked to discover that there were bird reserves, cliffs and woods marked. I had thought it was all mud flats, unexploded WWII ordnance, and of course, broken glass. The maps gave me an inkling: I was going to be surprised. Perhaps I should set aside old prejudices.

We are walking with different sets of people every day, people who love their stretch of coast for various reasons and have each adopted a mile of our way. Today we are also accompanied by several scientists from the CEFAS institute in Lowestoft, the body that advises the UK government on marine matters. Julie tells me that the white foam that is mounded up on the foreshore is actually a natural phenomena caused by algae. Sophie talks about plankton and their effect on fish populations. When we get to Kessingland, Liam points out how the shallow soft cliffs are being ripped apart by rising seas, at a rate of up to five metres a year. “That material then gets deposited as a sandbank and it’s also causing the Ness to grow.”

Further along the coast, trees are falling off the cliffs. Bits of wall and brickwork poke out the sand. The sea has no respect for human boundaries, nor for the value of land and house prices. The coast is relentlessly changing and human efforts to prevent it are puny and largely unsuccessful. At the Little Tern colony Karen tells me that the birds are drifting northwards every year. As the Ness grows they shift their nesting area to be close to where they like to fish for sand eels. Five days ago a storm ripped out another colony at Benacre and the birds have arrived here, sitting outside the fence that the RSPB has erected, like refugees wondering where to make a new home. Another fresh arrival, for the first time this year, are a pair of avocets that have bred three chicks and are aggressively defending their space. “We think they are helping the terns by being here,” says Sue, another volunteer, “They keep the gulls off.” The avocets stroll through the shallows, daintily inserting their improbably curved bills into the sand, oblivious to their saintly status among the terns. Change can be rapid and even devastating here, something we humans tend to dislike. A 500 mile walk is more than I have ever attempted and on this frst day it feels like an epic challenge, but the real challenge will be to tread lightly and alter my own my own, broken-glass-based, bias.

As I walk away from the tern colony a small boy, an eleven-year-old volunteer, is carefully erecting a little cairn of stones near the egg to warn walkers not to step on it.

Kevin Rushby