HUMBLE earthworms could hold the key to survival for one of northern England's declining birds.

The ring ouzel, the "blackbird of the hills", has been declining for many years and is increasingly scarce in areas such as the Yorkshire Dales.

A recent Royal Society for the Protection of Birds (RSPB) survey estimated that in 1972 there were between 8,000 and 16,000 pairs nationally, but that has dropped to between 5,680 and 11,360, a disappearance from almost 30 per cent of sites.

Now the RSPB is supporting research by Cambridge University, which has confirmed that managing moorlands to create a habitat for worms could help the bird survive.

The research discovered that although the birds nest in heather moorland areas, usually on crags or steep slopes, they feed mainly on earthworms in short grass.

Now the RSPB is urging moorland landowners to manage their uplands to provide a mix of heather and grassland.