A small herd of water buffalo used to develop a nature reserve in Mid Wales has more than trebled, wildlife wardens have announced.

But the unexpected birth of a calf to one of seven buffalo brought in to help three existing animals graze the reserve in the west of Powys, came as a complete surprise to Montgomeryshire Wildlife Trust.

Trust staff who look after the herd on the Cors Dyfi Reserve, near Machynlleth, said they had no idea one of the extra animals was pregnant.

“We are celebrating our new addition but it came as a complete surprise to us,” said Montgomeryshire Wildlife Trust’s reserves officer, Tony Senior.

He said mother and baby were doing well.

Mr Senior added that the pair had been moved off the Cors Dyfi reserve to a nearby field because the ground was too rough for the youngster at the moment.

“We arrived here two weeks ago to look at the site and the animals and someone spotted the calf.

“It came as a complete surprise.

“We’ve moved mother and calf until she’s capable of coping on the reserve, but we expect her to return in about six months.”

Mr Senior said the mother and six others joined the existing herd of three recently.

The herd is being used as an alternative to native cattle to help turn a forestry plantation into a wildlife habitat for animals such as otters.

Mr Senior said the buffalo – the first of which were introduced just over a year ago – had transformed the reserve, munching and trampling young trees like willow and birch, and creating muddy wallows for wading birds.

Mr Senior said they were tried out as an alternative to native cattle that would not eat a diet of gorse, birch and willow, to develop the site as a varied habitat.

The Asian water buffalo weigh about half a tonne each and had been used successfully by other organisations in the UK to manage land. Mr Senior said: “Buffalo are more hardy and are being used as a grazing tool.”

Deborah Knox