A nature reserve in a landlocked county has become a "vital" roosting site for five endangered species of gull.

The Herts and Middlesex Wildlife Trust said its Hilfield Park Reservoir Nature Reserve, between Elstree and Bushey, Hertfordshire, had become a refuge for the seafaring birds, including herring gulls, which are currently in decline.

The trust said that although they were commonly known as "seagulls", scientifically "there is no such thing".