From the letter page...
Adventure Comics No. 318 (Mar 1964)
SMALLVILLE MAILSACK
Dear Editor: As a new reader of your magazine, I would like to know more about the "Legion of Super-Pets." Could you list the various creatures who belong to this super-menagerie? - Sandy Tail, Great Neck, N.Y.
(The super-creatures include: Super-Horse, Krypto, Super-Monkey, Streaky, Proty II and, coming up soon, Super-Bird. Incidentally, how many readers would like to see "Krypto-Mouse," featured in the Hall of Fame classic story in this issue? -Ed.)
http://members.shaw.ca/legion_of_super-heroes/letter_columns/Super-Bird?!? :shock: