After giving birth to 45 children most mums might think of putting their feet up and taking a well earned rest, but not so for one red squirrel whose prodigious breeding efforts are helping safeguard the future of her species.

Supermum Tortoiseshell has racked up nearly a half century of kittens at the Penthorpe nature reserve, near Fakenham, since 2008, greatly contributing to the East Anglian Red Squirrel Group's breeding programme.

Ed Bramham-Jones, head warden at Pensthorpe, said one secret of her success was the understanding she has developed with her mate Tweedledum.

He said: 'They are an amazing pair. They are quite funny as well because when Tortoiseshell has her kittens, Tweedledum will often move out into a run or a box. He knows his place and lets her look after the kittens. They have a good understanding.

'They are incredibly adorable, cute looking animals and they are really playful when they are young. They can be quite mischievous at times and you go in with a bucket of nuts and they are jumping in the bucket. They are fantastic when you have a lot of kittens. They are incredibly active in showing off their aerial ability.

'They won't come out of their breeding area for about five weeks and then you often see these very sweet little faces looking out of the boxes.'

The couple's offspring are mixed with red squirrels at other breeding centres in the region to ensure a diverse gene pool.

In the past they have been used to populate Angelsey Island, where a cull has reduced the number of grey squirrels, which carry a virus that kills reds, but that programme's success means the East Anglian group is looking for new destinations.

Mr Bramham-Jones said Tortioseshell's offspring had proved to be a huge hit with Pensthorpe visitors, and helped to education people about the native British species, and the threats it faces.