Features

Alastair Driver is well-placed to talk about the wildlife commonly found in and around the River Thames, having worked on conservation of this world-famous river for 20 years.

Alastair lives in Sonning and often enjoys spotting wildlife in the Thames Valley Park nature reserve, close to the Oracle building in Reading.
Find below the top five saints and sinners of the Thames in terms of the natural world.

Depressed river mussels

Saints

1. Depressed river mussels. These freshwater river mussels are an endangered species, under threat due to pollution and river dredging, but there are good populations in the Thames – including the stretch from Reading to Sonning. The species' name comes from the flattened shape of its shell.

A muntjac deer

2. Muntjac. These tiny deer can often be seen in the woodland close to the river bank. Originally from Asia, the muntjac was introduced to Woburn Abbey deer park in the 19th Century, and have since escaped into the wild. The native roe deer can also be seen along the riverbank.

3. Kingfishers: There are two pairs of breeding kingfishers along the Thames close to the Thames Valley park nature reserve  Kingfishers are small unmistakable bright blue and orange birds which live near slow moving or still water. They fly rapidly, low over water, and hunt fish from riverside perches, occasionally hovering above the water's surface.

4. Water rails; these secretive relatives of the moorhen visit reedbeds in the Thames Valley during the winter months and some even stay around to breed in less disturbed areas. They have long, slightly curved red beaks and beautiful striped patterns on their flanks and wings, but are rarely seen, The most likely evidence of their presence will be their “squealing piglet” calls coming deep from within a reedbed!

5. Cuckoos: These birds visit the banks of the River Thames in summer, They are well-known as 'brood parasites', as the females lay their eggs in the nests of other birds, especially meadow pipits, dunnocks and reed warblers.

American Signal Crayfish

Sinners

1. American Signal Crayfish have invaded the River Thames in recent years, and have spread the crayfish plague to which it is immune, but which has wiped out the native crayfish from the River Thames. American Crayfish live under stones and in burrows in the riverbank and are known to also reduce aquatic insect life.

2. Terrapins: Bought as cute pets and then abandoned by their owners when they grow larger, it's now not uncommon to spot terrapins or turtles the size of dinner plates in the River Thames, but they usually perish in hard winters.

3. American Mink: these voracious predators feed mainly on rabbits and fish, but their ability to swim and dive combined with their slim build, means that they can get into water vole burrows. This is not something that water voles had to cope with prior to the introduction of mink for fur farming during the middle of the last century. Now mink are known to be the primary cause of “Ratty’s” drastic decline in the last 30 years and there are hardly any water voles left anywhere on the Thames.

4. Floating Pennywort: This weed causes a problem in rivers. Originally imported for use in fish tanks, the weed has now found its way into the lower reaches of the River Thames. The weed can spread rapidly forming a dense covering which chokes waterways, and reduces light and oxygen vital for river life.

Canada Geese

5. Canada Geese: These birds are aggressive in numbers and occupy breeding habitats which would otherwise be used by birds such as moorhens and coots. They also cause a problem for humans, due to the large amount of goose droppings.