Yorkshire Arboretum red squirrels: New breeding colony of endangered red squirrels established on the Castle Howard estate in Yorkshire

Red squirrels are a native British species, but their numbers have suffered a catastrophic decline to due competition for resources with invasive grey squirrels, who also carry the squirrel pox virus that has devastated red populations.

The only wild colony in Yorkshire is at Snaizeholme in the Yorkshire Dales National Park, where grey squirrel numbers are carefully controlled by local landowners.

Although the Arboretum’s red squirrels will breed in captivity, the offspring will eventually be used to restock reintroduction programmes across the country.

Staff and volunteers designed and built the enclosure themselves,and it has a three-metre ‘no leap’ zone around it to keep the reds in and the greys out.

It covers 2,500 square metres of land, including numerous mature trees that provide suitable habitats.

Although there is no additional charge to visit the enclosure, booking is required.

Yorkshire Arboretum director Dr John Grimshaw said: “Our red squirrels form part of a nationwide project to ensure that there is a captive stock from which animals may become available for reintroduction to suitable areas as when conditions are suitable – i.e when grey squirrels have been eradicated.

"Long-term there are ambitions to reintroduce them locally, but there are other reintroduction projects elsewhere to which surplus kits from here might go, such as in Anglesey, and Cornwall. At present we don’t know where any youngsters might end up - if we get youngsters. It will certainly be a very long time before reintroduction hereabouts is conceivable.”

Reintroduction projects can be difficult to manage because all landowners in a wider area need to support control measures – namely culls – of grey squirrels to enable reds to establish themselves.

At Snaizeholme, the scheme is managed by the National Park Authority, who maintain a ‘buffer zone’ around the reserve, which was originally established by a local farmer. In recent years red squirrels have begun to spread beyond the area and into nearby towns and villages.