白头海雕仍面临着艰难时期。
被DDT浸泡过的鱼死了，被冲上岸边，白头海雕在那里大快朵颐。
Fish, soaked up DDT, died, and were washed up on shores, where bald eagles feasted on them.
从那时起，野生生物生物学家将白头海雕从加拿大重新引入美国。
Since then wildlife biologists had reintroduced bald eagles from Canada to America.
曾经有超过五千对白头海雕在全国各地筑巢，但到了1960年这一数字已降至四百以下。
Once, more than fifty hundred pairs of bald eagles nested across the country, but by 1960 that number had fallen below four hundred.
我们知道，白头海雕一直以海洋动物的尸体为食。
We know that [the eagles] have always fed on dead Marine animals.
但夏普认为，这种局面不可能出现：“白头海雕倾向于选择最普遍的食物来源，”他说。
But Sharpe thinks such a scenario is unlikely: "Bald eagles tend to feed on what's most prevalent in the environment," he said.
除了仔细监测白头海雕的动态之外，在保护白头海雕这一点上，科学家能做的很少，夏普说。
Besides monitoring the eagles carefully, there is little scientists can do to protect the birds, Sharpe added.
根据这些数据，科学家们重现了约25000年前至今在该区域的白头海雕饮食结构。
Based on that data, the scientists reconstructed the bald eagle's regional diet from about 25, 000 years ago to the present.
白头海雕饮食历史回溯。
白头海雕不太可能以稀有物种为食。
白头海雕常掠过水面捕鱼，并抢夺鹗抓到的鱼，也吃腐肉。
Bald eagles snatch fish at the water surface, rob osprey of fish, and eat carrion.
雕刻提供了一个干净，清晰的轮廓像上面这些漂亮的具体的形象造成的，白头海雕或五颜六色的蝴蝶。
Engraving provides a clean, crisp outline resulting in beautiful concrete images like those shown above, Bald Eagle or colorful butterfly.
白头海雕常掠过水面捕鱼，并抢夺鹗抓到的鱼，也吃腐肉。
Bald eagles snatch fish from the water surface, rob osprey of fish, and eat carrion.
下面黑色独玉摘雕一只栩栩如生的喜鹊，白头黑尾，摘色干净，更显喜庆吉祥。
Below unattended black jade carved a lifelike pick the magpie, a white-haired black tail, picked clean color, more a symbol of auspiciousness.
研究小组发现，曾经作为白头海雕捕食对象的海鸟种群，如布氏鸬鹚和卡辛氏海雀，在海峡群岛上的数量大大减少。
The team found that populations of seabird species the eagles had historically preyed on, such as Brandt's cormorant and Cassin's auklet, are now greatly reduced on the islands.
为了探明再引入的白头海雕如何影响已有的生态系统，纽瑟姆和他的同事对 这种捕食者在海峡群岛上留下的历史和史前巢穴进行了分析。
To find out how the reintroduced birds might affect the modern ecosystem, Newsome and colleagues analyzed the remains of prey species left in historic and prehistoric nests on the Channel Islands.
但夏普认为，这种局面不可能出现：“白头海雕倾向于选择最普遍的食物来源，”他说。
S. But Sharpe thinks such a scenario is unlikely: "Bald eagles tend to feed on what's most prevalent in the environment," he said.
根据这些数据，科学家们重现了约25000年前至今在该区域的白头海雕饮食结构。
Based on that data, the scientists reconstructed the bald eagle's regional diet from about 25,000 years ago to the present.
根据这些数据，科学家们重现了约25000年前至今在该区域的白头海雕饮食结构。
Based on that data, the scientists reconstructed the bald eagle's regional diet from about 25,000 years ago to the present.
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