Rare Animals: Top 10 Rarest Birds in the World

Below are some of the rarest, and therefore endangered, bird species in the world.

The Asian crested ibis (Nipponia nippon) originally nested in eastern Russia Japan and China but, presently, the only known remaining population of the species could be found in mainland China's Shaanxi Province. In 2006, the number of the species on record is around 500. The Asian crested ibis' favored habitat is in areas where there are trees where they can roost and nest and wetlands where they can feed.

Belonging to the merganser duck family, the Brazilian merganser (Mergus octosetaceus) is considered to be one of the most threatened waterfowl in the world with only 250 individuals left. The last confirmed locations of the duck/bird are Brazil and some parts of Argentina.

The Christmas Island frigatebird (Fregata andrewsi) bird species is endemic to the Christmas Island in Australia. In 2003, the population for the seabird is pegged at 2,000-4,000 mature individuals. They nest in tall forest trees.

Endemic to India, the forest owlet (Athene blewitti) was considered extinct until it was rediscovered in 1997. Although the species has been spotted in various forests in India since its rediscovery, it still remains in the Critically Endangered list with less than 250 individuals on record.

A large bird with similarities to the ostrich in appearance, the great Indian bustard (Ardeotis nigriceps) is a bustard found in India and some regions of Pakistan. The species' natural habitat are open countries and semi-arid grasslands. As of 2008, there are at least 1,000 individuals left of the species.

Due to extreme habitat loss, the population of the Honduran rmerald (Amazilia luciae) is pegged at somewhere between 250 and 1,000 individuals. Presently, the species from the hummingbird family is located at three sites in northeast Honduras.

The kakapo's (Strigops habroptila) name is derived from the Maori word for night parrot. This flightless nocturnal bird is endemic to New Zealand and as of 2010, there are only at least 130 individuals believed to be alive. The bird has a special place in Maori tradition and folklore.

Belonging to the hummingbird family, the marvellous spatuletail is made (Loddigesia mirabilis) unique by two outer tail feathers in the male of the species that end in discs or "spatules". Endemic to the forests of Peru, the current population of the species is somewhere between 250 to 1,000 individuals.

Presently, the Critically Endangered palila (Loxioides bailleui) can only be found in Hawaii, particularly on the slopes of Mauna Kea. This species of the Hawaiian honeycreepers is believed to total, at the most, 4,400 individuals.

The scaly-sided merganser (Mergus squamatus) can be found in various parts of Asia (including Russia) but majority of the species occurs in China. With the entire population estimated at fewer than 2,500 individuals, this species is listed as Endangered.