feeding pied wagtail

Hi all, I am a disabled lady, a prisoner in my own home in NE Scotland due to severe weather, I desperately need help, I have a pied wagtail who spends his days in my garden in bad weather, I usually feed him meal worms, however, despite ordering some more, they will not arrive for several days yet (if I'm lucky) I have now run out of these. Is there something else which he will eat when insects are scarce? I have tried him with everything I can think of but he ignores it and sits, as if waiting for me to bring his worms out. I am getting very concerned about him because we are having sub-zero days let alone nights and I'm worried he isn't going to survive without something. I would be most grateful for any advice offered.

regards,

gran