Identify this book

Cafe Society
1

Someone on a mailing list I subscribe to asks for the name and author of the following book (from about 1975 or earlier):

I remember (only) that it involved a child who, while playing a certain (magical?) recorder, was able to communicate with animals telepathically. I think there was a mentor-figure as well.

2

This sounds like the children’s show H. R. Pufnstuf.

3

This is probably H. Philip Birdsong’s ESP, in which a veterinarian’s son learns that when he plays an old recorder he can communicate with animals.

4

The person who asked about this book says that it’s indeed H. Philip Birdsong’s ESP.