Ruby the Robin by Patience Powell. The illustrator isn’t credited but the illustrations have the initials TK.
A Peekobook. Printed and Published by Perry Colour Books Ltd. 11 Buckingham Street, London W.C.2. I think it’s pre-1940s, but there is no date. One of a series.
Ruby the Robin is a cautionary tale of what might happen if you are a robin and you spend too much time shopping for hats.
While Ruby is in Peter Robin and Sons trying on hats she wishes that she could keep one of the hats on forever. A ‘queer little man all dressed in green’ suddenly appears and grants her wish. But all the other birds laugh at her and the hat won’t come off. Finally the little man relents and grants Ruby her wish to be rid of the hat.
Apparently ‘There are more important things to do in life than buy new hats all day.’ Words to live by surely?! The story ends with the line, ‘Now Ruby is a wiser bird and often goes hunting for crumbs and berries with the other little robins, instead of spending all her time looking in shop windows.