Rarest bird

The North American ivory-billed woodpecker (Campephilus principalis principalis) is currently the world's most endangered bird. North America's second biggest woodpecker (only the imperial woodpecker is bigger), it was believed extinct since the 1940s, until a Big Woods Conservation Partnership expedition, led by Cornell University's Cornell Laboratory of Ornithology and the Nature Conservancy, released a video filmed on 25 April 2005 that shows a single male specimen discovered during their intensive year-long search for this species in the Cache River and White River national wildlife refuges of Arkansas. Diagnostic double-raps and tin-horn-like calls, again characteristic of the ivory-bill, were also recorded there by the expedition, whose team members hope that other specimens exist still-undetected in this locality's vast wilderness. The ivory-bill's Cuban subspecies was briefly rediscovered in 1986, but no confirmed sightings have been reported since then, leading to speculation that it is now extinct.

The Kauai o-o (Moho bracattus), a species of Hawaiian songbird, was rediscovered in 1960, but is now only believed to number two pairs, with none in captivity. Most of the captive specimens of the Japanese crested ibis (Nipponia nippon) are unfortunately too old to breed, while those of the New Zealand kakapo or owl parrot (Strigops habroptilus) are mostly male.

[NB: Karl Shuker has included the subspecific name here (the second principalis), to differentiate the North American ivory-billed woodpecker from the Cuban ivory-billed woodpecker, a separate subspecies, which was still alive as recently as the 1980s.]