The closer you look, the weirder Mother Nature appears. Some birds that look absolutely common on the outside have anatomical features that will surprise you.
These birds have a long way to breathe! The purpose of extra elongated windpipes has to be the sounds these birds make.
Trumpeter swans, Whooping cranes and Trumpet birds are the noisiest members of their respective groups, and exhibit the most complicated and elongate tracheae of their respective groups. I think we can safely infer that extinct birds with long, looping tracheae - like those moa - made loud, striking calls too.
After all, these pipes closely resemble the loops in tubas, french horns, and trumpets.
The Lake Rapist
Argentine lake ducks practice forced copulation and the females are often observed trying to get away. Possibly the long penis evolved to make reaching a female easier. Or conversely, the long penis could be the reason the females try to escape.
If it weren't for the relatively photogenic hyoid bone left behind when the flesh is gone, you wouldn't believe this bizarre layout, The woodpecker's tongue is a bone of contention between creationists (who believe this bizarre configuration couldn't have evolved) and evolutionists (who say it could and did). My brother once told me that woodpeckers use their tongues to hold their brains in place while they hammer on trees. I didn't believe him. That idea doesn't seem so far-fetched now.