As part of the rivercare project Keep Britain Tidy will be putting together features on a variety of wildlife. Please click on the links below to find out more about the rivercare key wildlife.

European Otter (lutra lutra)
After many years of decline, otter populations are showing encouraging signs of increasing in parts of East Anglia.

Agricultural intensification in the post-war period led to increased use of toxic organochlorine pesticides and the loss of riverine habitats. The otter was almost extinct in Norfolk by the early 1980s.

Aided by the Otter Trust's reintroduction programme in the 1980's and 90's, the future now looks more promising. However, otters are still highly vulnerable to threats such as poor water quality, low fish populations, road deaths plus their slow breeding rate and fragmented populations are factors hindering their return.

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As such, the key to restoring otter populations is restoring healthy rivers and well managed wetlands where otters can thrive. This is the aim of the Anglian Otters and Rivers Project which is actively working with local people and landowners in Norfolk, Suffolk and Essex.

Based at Norfolk and Suffolk Wildlife Trusts, this project is seeing further good prospects for the otter and Norfolk is becoming a relative stronghold for them in comparison to some other parts of England. If you would like further information on the Anglian Otters and Rivers Project, please contact Steve Henson at Norfolk Wildlife Trust on 01603 625540 or at steveh@nwt.cix.co.uk.

• The UK has a single species of otter, the European or Eurasian otter lutra lutra - related to the stoat, weasel, badger and American mink
• Otters are legally protected in Britain and are a priority UK Biodiversity Action Plan species
• Otters are one of our largest mammals measuring up to 120cm from nose to tail tip - males are heavy weighing up to 10kg - females are about 30% smaller and lighter
• Otters have a medium to dark, chocolate-coloured coat and an off-white chest - not to be confused with the introduced American mink which is cat-sized with very dark brown fur
• Otters have a home range of up to 40kms covering watercourses and wetlands
• Mink are not a threat to otters - both co-exist along rivers in many areas
• In water, otters hunt by sight and touch, their sensitive whiskers pick up the vibrations of fish swimming nearby
• Otters mark their ranges with droppings known as spraints - spraints have a very a distinctive odour similar to that of jasmine tea or newly mown hay!

The Pool Frog (rana lessonae)
The pool frog is one of the rare and threatened British animals, plants and fungi the Government is trying to promote under its national Biodiversity Action Plan (BAP).

The pool frog is one of a group of frogs collectively known as the 'water frogs' or 'green frogs'. The pool frog was not considered to be native to Britain. However, recent archaeological and genetic studies indicate it may have been present in East Anglia in 300AD. Unfortunately 1993 was the last year a frog was seen in the wild.

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The reason for decline of the species is largely unknown. Several factors are suspected, such as reduction in the number and quality of suitable ponds and reduction in quality of habitat.

Anglian Water is the pool frog champion under the National BAP and is working closely with the Species Recovery team in English Nature on this project which is part of the company's biodiversity plan to protect and enhance the environment.

As there was only one known British male frog, new surveys are be carried out to discover if there are any other populations still surviving in East Anglia. If no new British frogs can be found, studies into historic sites for potential re-introductions will be undertaken.

While these surveys are ongoing, a breeding programme is being undertaken . This will ensure that offspring with the closest genetic make-up to the British frog will be re-introduced.

• Adults can grow up to 9 cms. in length but males are significantly smaller.
• Unusually for frogs, the members of the Green Frog complex will bask in the sunshine on even the hottest of days.
• It was presumed extinct in the wild at the last remaining site by 1995. A single individual known from this population survived in captivity until 1999
• The spawn 'rafts' are typically much smaller than the Common Frog's and individual eggs are brown above and yellowish below.
• The tadpoles can grow extremely large (up to 40 mms). And unless we have a long hot summer they will over-winter as tadpoles and metamorphose the following Spring.