A BIRD once extinct in Britain has been spotted at Oldbury power station.

Twitchers recently identified a female Great Bustard feeding in a field near the site's lagoon.

Great Bustards are the largest flying birds in the world, with some males weighing up to 20 kilograms.

There is a marked difference in size between the genders. Females are sometimes as much as 50 per cent smaller than males, the largest difference of any bird species and most other vertebrates.

The sighting was made by the Dursley birdwatching group which visits the site regularly to record bird species using the rich habitats around the station.

It is thought the bird could be one of a group recently introduced to the country from Russia by the Great Bustard Group (GBG).

The reintroduction project, based at Salisbury Plain, is an attempt to create a sustainable population of Great Bustards over the next 10 years.

Until the end of the 18th century, Great Bustards were widely distributed in England on open chalk downland, grassy heaths and agricultural land.

The intensification of agriculture caused numbers to decline and, because they were a prized game bird, heavy persecution led to their extinction by around 1840.

The silt lagoons and meadows created around the station have developed much-needed habitats and feeding grounds for the birds, and the rich grasslands are perfect for Great Bustards.

During their visit the Dursley birdwatchers spotted 44 different species of bird around the station.

Kate Baxter, the station's environmental engineer, said: "The site has a proactive land management plan designed to encourage biodiversity and this combined with its rural location, means it supports a varied and interesting range of plants and animals.

"It' s very encouraging that a species such as the Great Bustard is visiting the station. The silt lagoon is also attractive to many other species in particular Dunlin, Lapwing and Curlew."

A specific Biodiversity Action Plan for the station was now being developed, she said.

An established nature trial exists around the site to allow visitors to experience the wildlife around the station and wider Severn Estuary.