Analysis of Camouflage

Beside the bare and beaten track of travelling flocks and herds
The woodpecker went tapping on, the postman of the birds,
"I've got a letter here," he said, "that no one's understood,
Addressed as follows: 'To the bird that's like a piece of wood.'
"The soldier bird got very cross -- it wasn't meant for her;
The spurwing plover had a try to stab me with a spur:
The jackass laughed, and said the thing was written for a lark.
I think I'll chuck this postman job and take to stripping bark."

Then all the birds for miles around came in to lend a hand;
They perched upon a broken limb as thick as they could stand,
And just as old man eaglehawk prepared to have his say
A portion of the broken limb got up and flew away.

Then, casting grammar to the winds, the postman said, "That's him!
The boobook owl -- he squats himself along a broken limb,
And pokes his beak up like a stick; there's not a bird, I vow,
Can tell you which is boobook owl and which is broken bough.

"And that's the thing he calls his nest -- that jerry-built affair --
A bunch of sticks across a fork; I'll leave his letter there.
A cuckoo wouldn't use his nest, but what's the odds to him --
A bird that tries to imitate a piece of leaning limb!"