来自澳大利亚、加拿大和美国等国家的科学证据清楚地表明，这种鸟类的数量下降了。
The scientific evidence from countries like Australia, Canada, and the USA clearly indicates a decline in the birds' numbers.
自1914年以来，科学家们已经知道，以V字形队形飞行的鸟类消耗的能量更少。
Since 1914, scientists have known that birds flying in formation—a V-shape—expend less energy.
加拿大科学家发现了一个令人担忧的新例子，证明鸟类具有四处传播东西的力量。
Canadian scientists have found a worrisome, new example of the power that birds have to spread stuff around.
尽管有许多证据表明鸟类是从陆生兽脚亚目恐龙进化而来的，但一些科学家仍然表示怀疑。
Although many lines of evidence indicate that birds evolved from ground-dwelling theropod dinosaurs, some scientists remain unconvinced.
他们发表在《科学》杂志上的研究成果，建立了曾经存在于古代鸟类羽毛中的色素的化学指纹图谱。
Their study, published in the journal Science, revealed the chemical fingerprint of pigments that once tinted the ancient bird's feathers.
此外，科学家们一直认为鸟类是某些恐龙的后代，上述研究结果也让戴尔博士提出了一个堪称新奇的假说。
Almost as an aside, the study of birds - which are widely believed to be descendants of some dinosaurs - has led Dr. Dial to a novel hypothesis.
比较而言，科学估计有大概100万种昆虫、28000中现存的鱼类，1万种鸟类和5400种哺乳动物。
For comparison there are more than 1 million species of insects listed by science, 28,000 living species of fish, 10,000 birds and 5,400 mammals.
比较而言，科学估计有大概100万种昆虫、28000中现存的鱼类，1万种鸟类和5400种哺乳动物。
For comparison there are more than 1 million species of insects listed by science, 28, 000 living species of fish, 10, 000 birds and 5, 400 mammals.
因此，通过比较这两种鸟类的基因，科学家们可以确认，这部分基因对于一个鸟类是否会唱歌而且会学习唱歌非常重要。
Therefore by comparing the genomes of the two birds, the scientists could identify the genes that are most likely to be important in singing and learning to sing.
正是这些介于爬虫类和鸟类之间的过渡物种有着如此相似的地方，因此其他科学家无疑地认为这次新发现并不将意味着争论的终结。
Such are the similarities between these transition species of reptiles and birds that other scientists believe that the new finding certainly will not mean the end of the argument.
科学家们说，据称是地球上最古老最原始的鸟类的“始祖鸟”可能根本就不是一只鸟。
Archaeopteryx, supposedly the oldest and most primitive bird on Earth, might not have been a bird after all, scientists say.
科学家们设置了一个鸟类的“卡西诺赌场”，在那里放上两个标志以供鸽子下赌注。
Scientists set up an avian casino in which pigeons could place their bets on one of two symbols.
科学家们早就知道，鸟类在不同的环境下的鸣叫是不同的，而市区的鸟是以更高的音调鸣叫。
Scientists have long known that bird songs vary in different settings and that urban songbirds in particular sing at a higher pitch.
科学家相信，也许鸟类宁愿不去尝试更多的机会——要避开所有如大黄蜂的长相、声音和飞行模式的昆虫就是为了避免被蛰。
The scientists believe that perhapsbirds prefer not to take any chances - and to steer clear of all insects thatlook, sound or fly like a bumblebee to avoid being stung.
科学家猜想鸟类依靠的视觉线索意味着他们更有可能去攻击那些看上去和它们平时看的不一样的蜜蜂。
The scientists expected birds to rely onvisual clues, meaning they would be more likely to attack bees that lookeddifferent from the ones they were used to.
在这个领域里，还有大量的困惑，作为科学家的威特莫尔教授尽力地去了解恐龙终结于哪里，鸟类又开始于哪里。
There is a great deal of confusion in the field says Prof Witmer as scientists try to understand where dinosaurs end and where birds begin.
因此，有科学家表示，研究者需要探讨的问题并非是鸟类如何获得羽毛，而应该是鳄鱼如何丧失羽毛。
So perhaps the question to ask, say some scientists, is not how birds got their feathers, but how alligators lost theirs.
这些化石还将有助于科学家研究早期鸟类的飞行机制。
The fossils will also help scientists work out the mechanics of how early birds flew.
其他科学家同意这次的发现能够从根本上改变我们对鸟类的认识。
Other scientists agree that the discovery could fundamentally change our understanding of birds.
信鸽有高超的认路归巢的本领。科学家们已经揭开了信鸽认路的奥秘：这些鸟类飞行家像人类一样沿着公路前进。
The secret of carrier pigeons'uncanny ability to find their way home has been discovered by scientists: the feathered navigators follow the roads just like we do.
科学家们说，如果这两种鸟类已经繁殖了的话，他们将早已发现遗传学上的“中间类型”——即来自这两个物种的基因的麻雀。
If the birds had been breeding, the scientists say that they would have found genetic "intermediates" - birds with genes from both species.
科学家们已经发现：生活在城市中的鸟类拥有更大的大脑，这是因为它们必须对觅食更加机智。
Birds living in cities have larger brains because they have to be more resourceful about finding food, scientists have discovered.
徐星发现的恐龙数量比当代任何科学家都要多，他表示，某些恐龙拥有鸟类特征，甚至长有羽毛。
Discoverer of more dinosaur species than any other living scientist, Xu Xing says some dinosaurs have birdlike traits, including feathers.
科学家估计，每过24小时，就有150至200种植物、昆虫、鸟类和哺乳动物灭绝。
Scientists estimate that 150-200 species of plant, insect, bird and mammal become extinct every 24 hours.
有人说，鸟类和恐龙在趾上的不同成了极少数的科学家仍旧不相信鸟类是由恐龙进化而来的最后抵抗。
Some say it's the last holdout for a handful of scientists still not convinced that birds evolved from dinosaurs.
奈茨博士说，事实上，这项发现使科学家最近弄清了为什么对某些鸟类，雄性羽毛似乎不如雌性鲜艳。
In fact, that finding allowed scientists to figure out recently why the males of some species of birds did not appear to have brighter plumage than the females, Dr. Neitz said.
徐星发现的恐龙种类比任何当代科学家都要多，他表示某些恐龙拥有鸟类的特征，甚至长有羽毛。
Discoverer of more dinosaur species than any other living scientist, Xu Xing, with a cast of parrot-faced Psittacosaurus, says some dinosaurs have birdlike traits, including feathers.
徐星发现的恐龙种类比任何当代科学家都要多，他表示某些恐龙拥有鸟类的特征，甚至长有羽毛。
Discoverer of more dinosaur species than any other living scientist, Xu Xing, with a cast of parrot-faced Psittacosaurus, says some dinosaurs have birdlike traits, including feathers.
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