I took these photos in my back garden and cannot identify the bird on the nuts .It is not a really good picture but the markings  on the bird are quite distinct/ It is sleaker than it looks in the pictue with longer tail than shows. It is greeny grey with a cap It has a black and white tail and striped black and white on the wings. It has very unusual markings on the flank with a black patch speckled with white dots. It has a very long pointed beak and is slightly bigger and longer than the sparrows.The bird has visited several times in a pair and I cannot identify it anywhere. Can you help?

Eileen