Animals and plants listed as endangered species are removed only for two reasons. One is when they become extinct, and the other is when their populations have rebounded.

The United States' own list of endangered species delisted 21 species in October, mostly birds and mussels, for being extinct.

Conservationists strive to keep species on the list instead of causing them to die out or delisting them by increasing their kind in number. This requires painstaking monitoring of the species in the wild.

Kiwis, the fluffy, flightless bird with a long distinctive beak that is a beloved national symbol of New Zealand, where it can be found, are among the most challenging avians to observe.

Recently, the Capital Kiwi Project, which aims to promote the breeding of the bird in the hills of Wellington, New Zealand's capital, successfully produced four chicks, the first-born in the area in more than 150 years, Agence France-Presse reported.

"We are only monitoring a quarter of the 63 (adult) birds that have been released, so it is likely there will be more (chicks) out in the wild," project founder Paul Ward told AFP.

Meanwhile, a team of Oxford University scientists led by biologist James Kempton recently concluded a four-week expedition in the secluded terrain of northeastern Papua in Indonesia. They set up more than 80 remote cameras to record wild animals in the area with the help of local villagers in Yongsu Sapari.

The researchers seemed luckless, as they didn't find any significant photos until the last memory card was retrieved from the cameras. The images were of a small creature in the forest undergrowth of the Cyclops Mountains.

"There was a great sense of euphoria and also relief having spent so long in the field with no reward until the very final day," Kempton said of the moment he first saw the footage of the long-beaked echidna scientifically named Zaglossus attenboroughi.

The shy, nocturnal burrow-dwellers are notoriously difficult to find as they have only been scientifically recorded once before, by a Dutch botanist in 1961 or 62 years ago, according to Sky News.

WJG WITH AFP @tribunephl_wjg