The Kakapo, or Whakapapa (Strigops habroptilus), is a remarkable bird native now only to a select few islands on New Zealand: Maud Island, Fiordland, Whenua Hou, and Hauturu. It came over to the islands and, finding no mammalian predators, it lost the ability to fly. With colonization, however, and the introduction of predators like cats and rats, almost all Kakapo were destroyed. In 1995, only 50 known Kakapo survived. Today, there are 86 registered Kakapo.
The Kakapo has a few things which separate it from other species of parrot. For one thing, it, by far, weighs the most (up to 4 kilos). The male Kakapo also creates a sound no other animal in the world makes. When a male wants to get a female, it gathers air into a thoracic sac and produces a very deep "boom." This sound can be heard for well over 10 miles, as it sounds at such a low frequency. Each male may produce thousands of these noises per night, if it is competing with another. Once a male has mated, he leaves the female to do the work. He continues booming until he finds another female.