Estuaries are possibly one of the most productive environments on earth, with many unique communities of plants and animals adapted to living where freshwater rivers and sea meet.

They provide a source of food all year round for a variety of birds, mammals and fish species but their most important function is as a refuge for over-wintering wildfowl.

In Britain and Northern Ireland there are 159 major estuaries, the most in any country in North West Europe, and on the Island we have six: The East and West Yar, Newtown, The Medina, Wootton Creek and King’s Quay.

These were formed when the river systems to the north of what is now the Isle of Wight were flooded by rising sea levels about 10,000 to 12,000 years ago, creating the Solent, so in geological terms they are not particularly old.

The name ‘estuary’ comes from the Latin aestus (the tide) and aestuo (boil) where the sea and river meet.

They also have a distinctive smell caused by microorganisms in the exposed mud at low tide.

Ducks, geese and waders start to arrive in October, flying in from their breeding grounds from places as far apart as Greenland or Siberia to join the resident species in a safe winter environment.

The numbers can be quite amazing, especially along the East coast of England, and the Isle of Wight hosts its share.

For example, up to 1,000 Brent Geese (Branta bernicula) can be seen in the Newtown area in January and February and much the same around Bembridge.

Eurasian Wigeon peak at about 1,200 to 1,500 at Newtown and 600 to 700 in the Western Yar, with slightly smaller numbers at Bembridge.

Of the smaller waders, Dunlin, which is both a winter visitor and a passage migrant, are the most numerous with usually more than 1,000 at Newtown mid winter.

It should be noted that numbers do fluctuate year to year depending on conditions - a severe winter bringing more birds here from the mainland as they are forced south although, due to the more benign weather at the moment, this has not happened for a while.

During the spring months, estuaries are important feeding sites for migratory wetland birds on the move.

A visit to one of the Island's estuaries is always a treat whatever the time of year.