Woodland near Oxford is home to the densest population of badgers in the world -- but a census has revealed the animals are under threat from dry weather.

Chris Newman and colleague Christina Buesching inspect a badger sett in Wytham Woods

Last week, volunteers helped Oxford University scientists count badgers at 50 setts in Wytham Woods, the university-owned nature reserve on the north-west outskirts of the city.

Only 12 cubs were seen -- the lowest number recorded in the 28 years the census has been carried out.

Dr Chris Newman, mammal monitoring co-ordinator with the university's wildlife conservation research unit, said the annual count would typically spot 60 per cent of resident badgers. That suggested only about 20 cubs had been born this spring, and not all would be breeding females.

Only 15 cubs were spotted last year, a record-low figure at the time.

Dr Newman said Wytham had the most concentrated badger population in the world, but warned numbers could soon be significantly cut.

Recent dry springs meant earthworms -- the badgers' staple diet -- were difficult to find.

"As feared, cub numbers are very low," he added. "It looks as if this dry spring has been very bad news.

"But the wetter weather now should provide plenty of food to give the remaining cubs the best possible chance.

"Only one sett had more than a single cub present, but at least this means the cubs are well dispersed, reducing competition within litters.

"It will be a concern in four or five years' time, when all the breeding stock will be derived from our small cohort of cubs.

"It's definitely something to worry about, particularly if the dry springs continue.

"We are going to be rather low on breeding adults."

Some cubs starved to death if their mothers were unable to produce enough milk. Others may have been deliberately killed by other badgers to ensure a few young ones survived with limited food available.

He said: "If starvation in spring fuelled infanticide within social groups, it may have been deliberate on the part of the badgers to put all their eggs in one basket."

Colleagues studying climate change predicted more dry springs to come, he added.

On a positive note, the number of adult badgers had increased slightly.

A total of 120 were seen, compared with 105 last year.

The census was carried out over three nights, with 175 volunteers turning out for the final session on Friday, May 9.

The results will be posted on the Internet at www.wildCRU.org