[trick-or-treat]

In my part of the world there's a cuckoo that pulls a heist on crows where the male makes annoying noises and the crows chase him off while the female cuckoo invades the nest and leaves an egg. When the egg hatches the bird inside looks nothing like a crow but the crow mama never catches on and pays child support until it's grown.

That cuckoo gets my vote for cleverest.

[vintermann]

What part of the world is that? I don't think European cuckoos target birds as large as crows, or even magpies.

[trick-or-treat]

SE Asia