《经济学人》双语：鸟类可以孤雌繁殖 （英语考试常考）
《经济学人》双语：鸟类可以孤雌繁殖？（英语考试常考）
文/Irene-自由英语之路
标题：
Avian reproduction
No sex please, we’re condors
An endangered bird may sometimes reproduce without males
鸟类繁殖
无性，秃鹰
濒临绝种的鸟类有时会在没有雄鸟的情况下繁殖
Paragraph 1：
FEW ANIMALS have come closer to extinction, and yet survived, than the Californian condor.
几乎没有什么动物能与加利福尼亚秃鹰相提并论，这类秃鹰接近灭绝，却还能存活下来。
Thousands died as a result of flying into electrical cables or being poisoned by lead shot from discarded game-animal carcasses.
数千只秃鹰因飞入电缆被电死（见文末补充资料）或被丢弃的猎物尸体的铅中毒死亡。
By 1982, there were only 22 left. These relicts were rounded up and brought into a captive-breeding programme that proved an astonishing success.
到1982年，只剩下22只。这些剩余的秃鹰被围捕起来，并被带进一个圈养繁殖计划中，这计划证明了一个惊人的成功。
Thanks to the efforts of a team of conservationists co-ordinated by the San Diego Zoo Wildlife Alliance there are now 329 condors flying freely in western North America, and 175 more in the care of various zoos.
由于圣地亚哥动物园野生动物联盟协调的一组自然资源保护主义者的努力，目前北美西部有329只秃鹰自由飞行，另有175只秃鹰由各动物园照管。
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Paragraph 2:
As the precision of those numbers suggests, these birds are among the most closely monitored in the world.
正如这些数字的精确性所表明的那样，这些鸟类是世界上被密切监测的鸟类之一。
It therefore came as a shock to Oliver Ryder, a geneticist at the alliance, when he discovered that two of the females he was scrutinising had laid eggs unfertilised by males, which then went on to hatch.
因此，该联盟的遗传学家奥利弗·莱德感到震惊，他发现他正在检查的两只雌鸟未经雄性受精就下蛋，然后继续孵化（见文末补充资料）。
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As Dr Ryder and his colleagues report this week in the Journal of Heredity, both females had had ample opportunities to mate, since each was housed with a male with which she had successfully reproduced in the past.
正如莱德博士和他的同事本周在《遗传杂志》上报告的那样，这两只雌鸟都有充足的交配机会，因为它们都与一只雄鸟同住，在过去，它们曾成功地繁殖过。
One of them, indeed, had raised a whopping 23 chicks before laying the fertile unfertilised egg in question. She and her mate then went on to raise two more.
事实上，其中一只在产下可育的未受精的蛋之前，已经养育了多达23只小鸟。她和她的同伴接着又养育了2只小鸟。
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Parthenogenesis, as this form of male-free reproduction is known, is common in invertebrates and not unheard of in vertebrates.
单性生殖是一种已知的无雄性生殖形式，在无脊椎动物中很常见，在脊椎动物中也并非闻所未闻。
Some snakes indulge in it. So do Komodo dragons.
有些蛇是单性繁殖。科莫多龙（见文末补充资料）也是如此。
But it has rarely been recorded in birds, and when seen (as it has been in domestic turkeys) it has always been in circumstances when no males were around and it was therefore the only reproductive option available.
但很少在鸟类中记录到这种情况，当看到这种情况时（就像在家养火鸡中一样），它总是在没有雄性的情况下出现，因此它是唯一可用的繁殖选择。
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In nature, it will hardly ever be the case that there are no males around.
在自然界中，周围几乎不会没有雄性。
On the other hand, it is hard to say whether parthenogenesis is happening in wild birds, because that would require intense genetic screening of nestlings of a sort that is rarely conducted in ornithological research projects.
另一方面，很难说野生鸟类是否发生了孤雌生殖，因为这需要对雏鸟进行严格的基因筛查，而这种筛查在鸟类研究项目中很少进行。
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In this instance, neither chick prospered.
在这种情况下，两只小鸟都没有健康成长。
One, which was released into the wild near Big Sur state park in California, failed to thrive there and probably died of starvation at the age of two—not an uncommon fate for reintroductees, unfortunately.
其中一只在加利福尼亚州大苏尔州立公园附近被放归野外，但未能在那里繁衍生息，很可能在两岁时死于饥饿，不幸的是，这对重新引入的鸟来说并非罕见。
The other, held in captivity as part of a breeding programme, nevertheless failed to breed, and died of complications from a foot injury when it was nearly eight years old.
另一只作为繁殖计划的一部分被关在笼子里，但未能繁殖，在它将近八岁时死于脚伤并发症。
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At the moment, therefore, it is hard to know whether Dr Ryder has stumbled on an intriguing and previously unperceived mode of avian reproduction, or an aberration of little wider significance.
因此，目前很难知道莱德博士是偶然发现了一种有趣的、以前未被察觉的鸟类繁殖模式，还是一种意义不大的反常现象。
But if condors, and possibly other bird species, are routinely reproducing by parthenogenesis, then some rewriting of the textbooks will definitely be in order.
但是，如果秃鹰可以，可能还有其他鸟类也可以，都是通过单性生殖进行繁殖的，那么一些教科书将要被重新改写了。
（恭喜读完，本篇英语词汇量477左右）
原文出自2021年10月30日《The Economist》Science & technology版块。
精读笔记来源于：自由英语之路，仅供个人英语学习交流使用。
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【补充资料】
鸟会被电死吗？（来源于网络）
“鸟停在输电线上 时，它的电压和电缆的电压相同，因此不存在被电死的危险。然而，如果它张开翅膀，碰到了某些电压不同的东西，比如说另一 根电缆，或是和地面接触的某点，那么电压差就会让电流通过， 马上把鸟煎熟。”
鸡/鸟下蛋要受精吗？
鸡生蛋本身不需要授精，不受精的鸡蛋不会孵化，受精的鸡蛋会孵化雏鸡。
母鸡生蛋是母鸡的排卵行为，鸡蛋是母鸡排出的卵，其外有一层硬壳，内则有气室、卵白及卵黄部分。
鸡蛋的形成:卵母细胞在卵巢内生长发育时，卵黄物质在卵内逐渐积累增多，随着卵母细胞内卵黄物质的增多，体积变大，卵泡突出卵巢表面。排卵时，初级卵母细胞完成第一次成熟分裂，排出第一极体，成为次极卵母细胞。
Komodo dragons: 科莫多巨蜥，又名科莫多龙，学名Varanus komodoensis（Ouwens,1912)，巨蜥科巨蜥属的一种动物。是已知现今存在种类中最大的蜥蜴。科莫多巨蜥凶猛，成体吃同类的幼体，有时吃其他的成体。能迅速运动，偶尔攻击人类；但主要以腐肉为食，每天出洞到几千米以外的地方觅食。
科莫多巨蜥已濒临灭绝，野外仅存5700只左右 ，印度尼西亚已在科莫多岛上建立国家公园，以使科莫多巨蜥的家族壮大 。
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【重点句子】（1个）
Parthenogenesis, as this form of male-free reproduction is known, is common in invertebrates and not unheard of in vertebrates.
单性生殖是一种已知的无雄性生殖形式，在无脊椎动物中很常见，在脊椎动物中也并非闻所未闻。
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