不會飛的鳥

It's a biological mystery that has confounded scientists for over a century: How did the world's tiniest flightless bird find its way to one of the world's most remote islands?

世界上最小的不會飛的鳥，到底是怎樣來到世界上最遠島之一的呢?這是困惑了科學家們一個世紀的生物學謎題。

The Inaccessible Island rail (Atlantisia rogersi), sometimes called the "bird from Atlantis," is only found in one place on Earth, the appropriately named Inaccessible Island in the South Atlantic Ocean, smack dab between Africa and South America. Because the bird is flightless, it's unclear how it could have found its way to such a far-flung place.

荒島秧雞(拉丁學名Atlantisia rogersi)，有時候也稱“亞特蘭蒂斯之鳥”，只在地球上的一個地方被發(fā)現(xiàn)過，該地在南大西洋，它有一個很合適的名字——難達島，剛好位于非洲和南美之間。

When the bird was first discovered, scientists guessed that perhaps its ancestors walked to the island at a time when sea levels were lower and a land bridge stretched out across the Atlantic. This theory also became the basis for assigning the bird its own genus, Atlantisia, an homage to the mythical lost city of Atlantis which, according to legend, had also been swallowed by the sea.

當科學家們首次發(fā)現(xiàn)這種鳥類時，他們猜測也許是它們的祖先還在海平面低的時候，就沿著橫跨在大西洋上的陸地橋走到了島上。這個理論后來成為了將鳥歸為秧雞屬的基礎，傳說是為了崇敬早已被海淹沒的亞特蘭蒂斯城的隕落。

But it now appears that this theory was mistaken. A new genetic analysis of the bird has revealed what its closest living relatives are, which has, in turn, provided some telling clues about how its ancestors may have found themselves in such a distant locale, reports Science Daily.

但現(xiàn)在看來這個理論好像是錯誤的。據(jù)科學日報報道，一項新的鳥類遺傳分析已經(jīng)揭曉了它們現(xiàn)存的最近親屬是誰，這也為它們的祖先是如何發(fā)現(xiàn)自己身處如此之遠的島上，提供了一些有效證據(jù)。

It turns out, this itsy-bitsy flightless bird probably got to Inaccessible Island by flyingthere about 1.5 million years ago. Of course, at that time it was not flightless; the bird likely evolved to become flightless as an adaptation to its remote habitat.

事實證明，這種迷你不會飛的鳥，很可能在約150萬年前就飛到了這座難達島上。當然那時它們還是會飛的，只是后來為了適應這種偏遠棲息地，最后很可能就不會飛了。

Although the Inaccessible Island rail is certainly an oddity, the study found that it has a distant relation to the dot-winged crake in South America and the black rail found in both South and North America. These birds are adept flyers, known to colonize habitats far and wide.

雖然荒島秧雞的確很奇怪，但該研究發(fā)現(xiàn)，它和南美的點翅秧雞，還有在南北美都發(fā)現(xiàn)過的黑田雞有著深遠的關系。這些鳥都很擅長飛行，也因“殖民”的棲息地廣泛而聞名。

"It seems that rail birds are extremely good at colonizing new remote locations and adapting to different environments," explained evolutionary biologist Martin Stervander, who conducted the research.

主管該項研究的進化生物學家Martin Stervander這樣說道：“秧雞們好像非常擅長‘殖民’又新又遠的地方，也很會適應不同的環(huán)境。

It might seem unusual for a bird so adept on the wing to ever give up the ability to fly for a life confined to the ground on a small island, but it's a fairly smart adaptation. Flying takes a lot of energy and resources, and resources aren't plentiful on small islands in the middle of an ocean. Furthermore, there are no land predators on Inaccessible Island, so there's no need for wings to escape. Instead, the bird is able to fill the niche that tiny rodents might occupy elsewhere, scurrying around through the vegetation.

對一只非常熟練飛行的鳥來說，放棄飛行，把自己限制在小小的一座島嶼上生活，真的很不尋常，但這確實是相當聰明的適應。飛行消耗大量能量和資源，而大海中的一片小島上本來資源就不充足。再說，難達島上沒有陸地掠食者，所以也沒必要需要翅膀逃亡。相反，這些鳥兒可以在植被中四處亂竄，以填補小的嚙齒類動物為了占領每個地方所挖的坑。

"The bird has not had any natural enemies on the island and has not needed to fly in order to escape predators," said Stervander. "Its ability to fly has therefore been reduced and ultimately lost through natural selection and evolution over thousands of years."

Stervander說：“這些鳥在島上還沒有任何自然敵人，也不需要為了逃開掠食者而飛走，它們的飛行能力因此也就降低了，最終通過幾千年的自然選擇和進化失去了飛行的能力。”

So, mystery solved. But this bird is truly one-of-a-kind, the last surviving member of a lost lineage that somehow found its way to a very unlikely habitat, and its rarity underscores the importance of making sure that it's protected. For now, Inaccessible Island is relatively pristine, with few introduced species that might compete with the bird. It will be important for conservationists to ensure that it stays this way.

所以謎題解開了。但該鳥真的是世界上不知為何能夠找到幾乎不可能的棲息地的，快要滅絕的血統(tǒng)中，唯一，也是最后的幸存成員了。它們的稀少也意味著保護它們的重要性?，F(xiàn)在，難達島還相對原始，只是有一些可能和它們競爭的鳥類存在。對自然資源保護者來說，保持這個島原本的樣貌真的很重要。