A new study by experts from the UK Biodiversity Action Plan has found 1,149 species are endangered in the UK. The pine marten is one of them.
There are probably just 300 to 500 bottlenose dolphins in UK inshore waters. This image was taken by BBC News reader Kirsten Goesmann at Chanonry Point near the Moray Firth.
Horseshoe bats are suffering because their favoured roosting spots, like hollow trees and old buildings, are disappearing. Greater use of Insecticides also means they have less to eat.
Skylark numbers halved in the UK during the 1990s and they are still in decline, largely due to changes in farming practice.
Smooth snakes are non-venomous and very rare. They are restricted to small areas in the south of England.
The red grouse is unique to Britain, but has suffered in recent years because of our increasingly mild winters. Warm weather encourages a parasite that attacks their gut.
The large blue butterfly disappeared from the UK in 1979, but has recently made a comeback to the highest level for at least 60 years.