Mudflats

What are they?

Mudflats are well named – they are muddy and flat! They are expansive areas of mud which are exposed at low tides and submerged at high tides, making them intertidal habitats.

Mudflats are valuable coastal defences as they dissipate wave energy before it reaches the land, and they are also important fish nurseries for species such as plaice. Threats to this habitat include dredging and development, global sea rises, and chemical pollution. Bacteria found in the mud releases gasses that can be quite pungent at low tides but is completely natural – it smells like rotten eggs!

The Solent coast is packed with mudflats with some of the largest examples in Langstone and Chichester Harbours. In the absence of manmade development, mudflats become saltmarsh as they spread inland.

How are they formed?

Mudflats are formed in sheltered areas of coastline such as estuaries and natural harbours, where the absence of strong waves allows the build-up of fine silt and clay sediments. The resulting mud is very fertile due to the high concentration of organic materials and this makes mudflats ideal homes for filter-feeding animals such as worms and molluscs.

The reason that the Solent has such a huge abundance of mudflats is because the Isle of Wight provides protection to the coast, reducing the power of the waves and currents that enter the Solent allowing sediment to build up.

Birds of the mudflats

Mud may look devoid of life to the human eye, but is full of plant life and small creatures. Due to the huge abundance of animals that live in the mud, it acts as an ‘all you can eat food buffet’ for birds.

Many waders enjoy searching for food that lives inside the sediment while ducks and geese enjoy munching on the plants that live on top.

Different birds are adapted to feed on different mud dwelling animals – birds with longer beaks can eat the animals who live deeper while shorter beaks are adapted for eating the animals which live near the surface.

This means you can spot many different species of birds using the same areas of mudflats as they don’t compete for the same food.

However, this ‘all you can eat buffet’ does have it’s downside, it’s only open when the tide is low which means feeding is limited to certain hours of the day. Birds who feed on mudflats can be found resting on high ground or manmade structures nearby when the tide is high, conserving energy and waiting for the mud to appear again. See the saltmarsh page to learn about this important habitat for birds who want to rest nearby to their muddy feeding grounds.