The Thames Estuary is an excellent example of the forces of nature at work. Here tide, sediment, plants, animals and time combine to create a special environment.
The great expanses of mud that can be seen from the South Essex shores at low tide play host to a wide variety of wildlife. Saltmarshes and mudflats, two of Britain’s last natural wildernesses, are formed as rivers deposit their load of fine silts and sands in the estuaries.
Where the silts are exposed to the ever-moving tidal currents, large areas of mudflats are formed. Mudflats are the most productive and protein rich habitat in the U.K. One square metre of Thames Estuary mud can hold up to 1,200 worms below the surface, while up to 15,000 snails called Hydrobia graze on its surface.
In sheltered bays, sediments build up. This is when salt tolerant plants like eel grass and glasswort (also called samphire) seize their opportunity. These hold the sediment, which increases the muddy build up and raises the level of the saltmarsh, which in turn allows other plants like sea aster to grow.
Although they are not very pretty to look at when the tide is out, the coastline and mudflats are one of the most important places for birds in the UK. Teeming with wading birds, ducks and geese, the mudflats and saltmarshes are a massive larder and sanctuary for up to 300,000 birds, which are protected by international laws. The neighbouring marshes are home to a rich variety of breeding birds, water voles and many rare plants, and seals can often be seen off the coast too.
A variety of birds take advantage of this rich food source. These come in a range of shapes and sizes from the dark-bellied brent goose to the smaller wading birds such as dunlin.
Look out for turnstones, who spend most of their time creeping and fluttering over rocks, picking out food from under stones and easily seen in flocks on Leigh seafront and Southend Pier. Turnstones have a mottled appearance with brown and black upperparts, white underparts and orange legs.
The curlew has a long, slender down-curved bill, a brilliant tool for extracting worms from deeper in the mud. As its name suggests, the turnstone is a bird equipped for doing just that, turning stones. Invertebrates under stones, such as sandhoppers, provide a valuable food source for this small, attractive bird.
Redshanks are abundant and widespread off coasts, and are medium-sized wading birds, larger than turnstones. As their name suggests, they have longish red legs and a long red straight bill, grey-brown above and whitish below.
A flock of dunlins (our commonest small wader) are busy birds, feeding in the shallows, with slightly down-curved bills and a distinctive black belly patch in breeding plumage. Dunlins are regularly joined by tiny little stints, while on sandy shores sanderlings may be scuttling around like clockwork toys, small, plump and energetic, it has a short straight black bill and pale grey above and white underneath.
Oystercathers are distinctive, noisy black and white birds with long bright red-orange bills, used for smashing open large molluscs such as mussels. Often seen on the mudflats around Southend and Leigh, feeding on cockles.
To have all this wildlife in profusion on the doorstep is one of the great bonuses of living in south Essex, and why the RSPB is keen to run events to share these all this with you.
The best way to discover more about these incredible birds along the Essex coast is to join us at some of our local events. Keep your eye on the Countryside and Wildlife events page for more information.
Community Project Manager
South Essex Marshes – Warden
Photographs Courtesy of the RSPB.
Redshanks by Andy Hay