Blackbird or Tui - which bird is it?

Last week I was invited to read In the Garden to the lovely, lively children at Sand Dunes early childhood centre. I listened very carefully to their comments and was pleased to see the slugs and spiders in our garden have as many fans as do the pretty and more obvious butterflies. What most interested me was that the children were confused between the tui and the blackbird, at least in the first reading of the book.

The cover shows a tui and it appears on other pages too.