Short answer: it's a frog.
Slightly longer answer: it's a Western Banjo Frog, also known as Lymnodynastes dorsalis, and it's found in the south-western corner of Western Australia. The male frog's call is like the plucking of a banjo string. When a group of males sing together, the chorus sounds like: pobblebonk.
And Pobblebonks is the title of Garry Fleming's picture book (Hodder Headline Australia, 1998).
"At the end of my street where the tall reeds grow, live the pobblebonks.
What are they? Do you know?"
There's a mysterious feel to the accompanying double page illustration. Just right for the beginning of what is essentially a rhyming puzzle for the young reader to solve. The narrator proceeds to explain about pobblebonks obliquely - by telling us (and picturing) features they don't have, what they don't eat etc. More clues are added until at last we discover a pobblebonk lives in a jar beside his bed. The end papers tell us some facts about the frog.
From what I can discover, Pobblebonks is no longer being published. It's definitely worth keeping an eye open for in secondhand stores or online (Amazon UK has one for 22 pounds!) Pobblebonks is a great book for young animal lovers, and would make a wonderful resource for students involved in environmental studies. I enjoyed it mostly as a puzzle book, because the illustrations are a collage of animal snippets, and it was fun to try to identify each creature.
Book Chook Tip: Puzzle books might be a way to get your reluctant reader interested in widening his range of reading. You could start with all visual puzzles like Where's Wally. Then introduce books with just a little text, like some of the I Spy books. Add more text gradually. Is this sneaky? Yes! Does it work? Absolutely!
Find more great non-fiction books at the ACPL Mock Sibert blog.