Experts have been surveying insects and plants at the ancient Uffington White Horse as part of a long-running project to assess wildlife at National Trust properties.

The team have been recording species on the wildlife-rich White Horse Hill site in Oxfordshire, renowned for its chalk figure and archaeological remains, to examine its condition 15 years after they last surveyed it.

It is part of the work of the National Trust's specialist "biosurvey" team which has been surveying its properties for 35 years.

In that time, experts have visited more than 1,000 sites, mapping 234,000 hectares of land and recording more than 16,000 different species of plants and animals.

Finds by the team at the Uffington White Horse survey include small blue butterflies, the UK's smallest butterfly species which need the flowers of the kidney vetch for their caterpillars to eat. Kidney vetch are flowering at the site.

The experts have also recorded the two-coloured mason bee which nests in old snail shells, the hill cuckoo bee which invades the nest of another bee and the orchid beetle whose larvae live underground and feed on roots.

There is also a "fantastic" show of orchids on the chalk grassland site, including the frog orchid, according to survey team leader and invertebrates expert Andy Foster, who has been examining the site alongside plant ecologist Richard Allen.

Mr Foster said there was a need to strike a balance in managing the site for its archaeology and its wildlife. Conservation measures include sheep grazing, but not in summer when it would damage the flowers and by moving the sheep around the site.

And he said: "It's very important site in Oxfordshire, because so many of the chalk grasslands have gone, and this is one of the better examples.

"The Bronze Age horse and the Iron Age fort are quite iconic for their mystique and history," he added.