California condor, the largest terrestrial bird in North America, with a wingspan of about 9 feet! Due to habitat destruction, poaching and poisoning from lead and DDT, the population of condors plummeted during the 20th century until only 22 were left in the entire world. A massive conservation effort that included capturing all remaining condors and starting a captive breeding program has helped to bring their numbers back up to a little over 400, with about 234 birds living in the wild.
20 of the World's Weirdest Endangered Animal Species
Kakapo "This is not only the rarest, but the strangest parrot in the world. Imagine a rather portly nocturnal bird that never flies, preferring to hike through hilly forest for miles every night. It weighs in as the heaviest parrot in the world at 8 pounds. Imagine this and you have the very real (but virtually extinct) kakapo. A resident of New Zealand, which is home to a number of rare birds, there are only 62 kakapos remaining on earth."