Called llatai songs in Welsh: Where blackbird (specifically?)acts as messenger between lovers. Blackbird aka Mwyalch, y fwyalchen is the diminutive. Occurs in fourth verse of version of y Gelynnen, the Holly, I know. It is out of place,probably a hen bennill.

Aderyn y tô a gafodd dy
A cheiliog dy'r fwy'n fwyalchen
Ac eistedd mae fannwylyd Gwen
Tan gysgod pren y gelynnen
Ffal dyral dy raldi.........