On a windy but pleasant October day we walked from Figueras to Castropol and back (about 8 miles). Figueras is about 20 minutes from 'Granero del burro', Castropol slightly less. They are both on the Eastern side of the Eo estuary which forms the border between Asturias and Galicia. If you do the walk form Figueras you can have a nice lunch in the port area of Castropol - Rison is a lovely little restaurant to eat in.
The Eo estuary is a fantastic place for wildlife and during the Winter months there are thousands of ducks - Wigeon, Teal, Pintail and Mallard. In October there were a few Spoonbills, lots of Little Egrets, Whimbrel, Grey Plover, Spotted Redshank, Black Tailed Godwit, Greenshank, Mediterranean Gull and a few late Sandwich Terns. It is always worth a look as there are lots of birds that turn up here on migration