So Owl wrote . . . and this is what he wrote:

HIPY PAPY BTHUTHDTH THUTHDA
BTHUTHDY.

Pooh looked on admiringly.

“I’m just saying ‘A Happy Birthday’,” said Owl carelessly.
“It’s a nice long one,” said Pooh, very much impressed by it.
“Well, actually, of course, I’m saying ‘A Very Happy Birthday with
love from Pooh.’ Naturally it takes a good deal of pencil to say a
long thing like that.”
“Oh, I see,” said Pooh.