VOA科学技术2024--Study: 610 Kinds of Birds Have Disappeared in Past 130,000 Years

New research says that 610 bird species have died off over the past 130,000 years.

For instance, the Kaua'i 'ō'ō, a Hawaiian songbird, was declared extinct just last year.

The recent research also suggested that an "ongoing¹ biodiversity crisis" that requires urgent study is taking place.

Bird species have a special purpose within the environment. When a bird species disappears, nothing remains² to do its job, suggested Tom Matthews of the University of Birmingham in England. Matthews was the lead writer of the study that appeared recently in the publication Science.

Matthews said that birds do many important jobs in an environment. These jobs include spreading seeds, eating insects, or reusing dead material. Vultures, for example, eat the flesh of dead animals.

Matthews said a good example of the importance of birds is "on the islands of Mauritius and Hawaii, where all or almost all the native...birds that eat fruit...have gone extinct."

He explained, "In eating the fruits and then moving around, birds will disperse³ the seeds of the plants the fruits belong to." The lack of seed spreading can have secondary effects, Matthews said. For example, Mauritius now has many threatened tree species.

Most of the documented extinctions have taken place on islands.

The loss of living areas for birds can have big effects given the limited area involved. Many island birds are flightless, meaning they cannot fly away to escape predators⁶.

As a result, flightless birds are easily hurt by new predators, such as rats or cats, Matthews suggested.

Human hunting of birds was a big reason behind the disappearance⁷ of different bird species in the past. Bird hunting remains a big problem in some areas. Capturing birds for the songbird trade is a big problem, particularly in Southeast Asia, Matthews said.

Some areas and species had more exact reasons for bird disappearances⁸. For example, avian malaria⁹, introduced by people, has resulted in large numbers of extinctions in Hawaii where the birds possessed¹⁰ no natural immunity¹¹.

Matthews suggested that the effects of a changing climate on birds remains a "big unknown."

Many birds have been lost over time.

The large flightless "elephant birds" were native to Madagascar. The bird is believed to have disappeared after people arrived. That includes Aepyornis maximus. It was about 3 meters tall and was possibly the largest bird that ever existed.

The flightless moa birds, native to New Zealand, including the South Island giant moa, also disappeared after humans came to the islands.

North America's passenger pigeon numbered in the billions but was hunted to extinction⁴.

The researchers said the 610 bird species combined represented 3 billion years of evolutionary¹² history. Each lost species is like cutting off a branch from the tree of life.

The number 610 is "likely a large underestimate" of avian extinctions, Matthews said. This is because of a lack of data from some areas and the fact some lost species may not have left behind bones or other evidence.

Matthews added, "the vast majority of extinctions over the last 50,000 years are attributable to human actions."

About 11,000 bird species now exist. The researchers projected future extinctions of more than 1,000 species over the next two hundred years.

"So even if you don't care about the moral and ethical¹³ concerns regarding the loss of species, these extinctions are important for other reasons, such as the loss of species that helped the environment to function effectively," Matthews added.

Words in This Story

species - n. a class of animals having common attributes and designated by a common name

extinct - adj. no longer existing

disperse - v. to cause to become spread widely

predator⁵ -n. an animal that hunts and eats other animals

vast -adj. very great in size or extent

attributable - adj. to be explained by indicating a cause

ethical -adj. related to questions of right or wrong

function - v. to operate or be in action

1 ongoing   

adj.进行中的，前进的

参考例句：

• The problem is ongoing.这个问题尚未解决。
• The issues raised in the report relate directly to Age Concern's ongoing work in this area.报告中提出的问题与“关心老人”组织在这方面正在做的工作有直接的关系。

2 remains   

n.剩余物，残留物；遗体，遗迹

参考例句：

• He ate the remains of food hungrily.他狼吞虎咽地吃剩余的食物。
• The remains of the meal were fed to the dog.残羹剩饭喂狗了。

3 disperse   

vi.使分散；使消失；vt.分散；驱散

参考例句：

• The cattle were swinging their tails to disperse the flies.那些牛甩动着尾巴驱赶苍蝇。
• The children disperse for the holidays.孩子们放假了。

4 extinction   

n.熄灭，消亡，消灭，灭绝，绝种

参考例句：

• The plant is now in danger of extinction.这种植物现在有绝种的危险。
• The island's way of life is doomed to extinction.这个岛上的生活方式注定要消失。

5 predator   

n.捕食其它动物的动物；捕食者

参考例句：

• The final part of this chapter was devoted to a brief summary of predator species.本章最后部分简要总结了食肉动物。
• Komodo dragon is the largest living lizard and a fearsome predator.科摩多龙是目前存在的最大蜥蜴，它是一种令人恐惧的捕食性动物。

6 predators   

n.食肉动物( predator的名词复数 )；奴役他人者（尤指在财务或性关系方面）

参考例句：

• birds and their earthbound predators 鸟和地面上捕食它们的动物
• The eyes of predators are highly sensitive to the slightest movement. 捕食性动物的眼睛能感觉到最细小的动静。 来自《简明英汉词典》

7 disappearance   

n.消失，消散，失踪

参考例句：

• He was hard put to it to explain her disappearance.他难以说明她为什么不见了。
• Her disappearance gave rise to the wildest rumours.她失踪一事引起了各种流言蜚语。

8 disappearances   

n.消失( disappearance的名词复数 )；丢失；失踪；失踪案

参考例句：

• Most disappearances are the result of the terrorist activity. 大多数的失踪案都是恐怖分子造成的。 来自辞典例句
• The espionage, the betrayals, the arrests, the tortures, the executions, the disappearances will never cease. 间谍活动、叛党卖国、逮捕拷打、处决灭迹，这种事情永远不会完。 来自英汉文学

9 malaria   

n.疟疾

参考例句：

• He had frequent attacks of malaria.他常患疟疾。
• Malaria is a kind of serious malady.疟疾是一种严重的疾病。

10 possessed   

adj.疯狂的；拥有的，占有的

参考例句：

• He flew out of the room like a man possessed.他像着了魔似地猛然冲出房门。
• He behaved like someone possessed.他行为举止像是魔怔了。

11 immunity   

n.优惠；免除；豁免，豁免权

参考例句：

• The law gives public schools immunity from taxation.法律免除公立学校的纳税义务。
• He claims diplomatic immunity to avoid being arrested.他要求外交豁免以便避免被捕。

12 evolutionary   

adj.进化的；演化的，演变的；[生]进化论的

参考例句：

• Life has its own evolutionary process.生命有其自身的进化过程。
• These are fascinating questions to be resolved by the evolutionary studies of plants.这些十分吸引人的问题将在研究植物进化过程中得以解决。

13 ethical   

adj.伦理的，道德的，合乎道德的

参考例句：

• It is necessary to get the youth to have a high ethical concept.必须使青年具有高度的道德观念。
• It was a debate which aroused fervent ethical arguments.那是一场引发强烈的伦理道德争论的辩论。