One of the top wildlife success stories of recent decades has been the phenomenal increase and spread of the Canada goose.

Many Essex reservoirs, lakes, flooded gravel pits and smaller waters now support numbers of these distinctive birds, which were first introduced into Britain in the 17th century for their ornamental value.

Now another member of the wildfowl family may be emulating the fortunes of the Canada goose, though it is unlikely to be on such a grand scale.

The greylag, the largest of our native geese, and from which most farmyard geese are descended, is becoming firmly established, and shows promise of increasing both its numbers and range.

Greylags became extinct in England as breeding birds in the 19th century, but the situation has changed markedly since that time.

Following introductions by wildfowlers, mainly in the 1960s and 1970s, greylags have become re-established, and are now resident in much of eastern and southern England.

It was also in the 1970s that these birds were first released in Essex. The chosen site was the coastal waters of Hamford Water, where feral domestic geese had been nesting for many years. Later, more introductions took place at other sites, including Goldhanger, Tollesbury and Abberton Reservoir.

Today, greylags are present in widely dispersed locations across Essex. Their numbers may comprise not only the descendants of introduced stock, but new arrivals from outside the county, and escapees from wildfowl collections.

While much of their traditional wetland habitat has been lost, greylags have adapted to colonising lakes, reservoirs and flooded gravel pits, where they often associate with Canada geese. They are prone to predation by foxes and other predators, so waters with islands are often selected for nesting.

While wildlife conservationists welcome the return of the greylag, farmers are less pleased. The geese forage on agricultural land and consume a wide variety of crops. They can also damage pasture land by intensive feeding and trampling.

During the wildfowling season greylags are legal quarry, but at other times they can only be controlled under licence. This may be done by egg-collecting, shooting, or by scaring.

Most of our resident greylags do not travel far afield, unlike their Icelandic relatives. Each autumn in October and November, Iceland’s greylags leave their homeland and head south for Britain, with some 80,000 to 90,000 birds making a sea crossing of about 400 miles. Some travel no farther south than Scotland, but many continue their migration into northern England.

By marking the birds with plastic collars or coloured leg rings and releasing them back into the wild, ensuing sightings may throw new light on the extent of their travels.

The future may expose some surprises about the range of the journeys made by these comparative newcomers to our county.

GORDON STRUTT