[Tim] He sounds pretty close. — [Ed] Out of all the birds-of-paradise, one of the most haunting and intriguing vocalizations comes from the curl-crested manucode. This species is only found on a few islands just off the far eastern tip of the island of New Guinea. [Papua New Guinea] We had the opportunity to see them and Tim photographed them on an exhibition to Ferguson Island in 2005. And even though we heard their incredible vocalizations back then, we never had a chance to film the behavior until our very last expedition in 2011. These manucodes are not as sexually dimorphic as the other birds-of-paradise. The males and the females look the same. They travel around in pairs and they seem to maintain a territory together, and they are vocalizing both to stay in contact with each other – the male and the female – but also to defend their territory from other pairs. The reason the curl-crested manucode can make these incredible sounds is because they have a hidden feature under their skin, this really modified part of their anatomy, this elongated windpipe or their trachea. In most birds the trachea is just this straight tube that goes from the mouth into the lungs. But on the curl-crested manucode, where it’s extremely long and highly modified it comes from it’s mouth, but instead of going straight through to its lungs actually continues between the skin and the muscle and curls all the way around the length of its torso and loops back up. In some cases it even coils around the abdomen before coming back up and entering into the body to go to the lungs at the base of the neck. You’ll notice that just before he vocalizes he kind of rears back. You can see the neck filling with air and that’s that trachea filling up. And then as they vocalize they kind of lift their head up and roll forward a little bit and their wings kind of spread over their back, and their body lifts up and lunges. So the curl-crested manucode, they’re not the most extravagantly plumed of the birds-of-paradise but never-the-less is one of the most extraordinary out of the thirty-nine for the way that it sounds. — [Tim] Move down to the back. I got him once, though. — [Ed] Did you get that one? — [Tim] Yeah! [Explore more at birdsofparadiseproject.org, youtube.com/LabofOrnithology]

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At first look, manucodes appear almost normal compared to other birds-of-paradise. Males and females look alike, live in pairs, and males help raise the young. But on the inside manucodes have an exotic secret, and you can hear it in their voices. Males have a greatly lengthened windpipe that works like a wind instrument, creating a long, mellow, fluting song. Filmed and photographed by Tim Laman. Explore more at www.birdsofparadiseproject.org