字幕列表 影片播放 列印英文字幕 The bald eagle... one of the world's most fascinating birds of prey... Most recognized as the national bird and symbol of the United States, it is indeed one of Nature's Wonders. Its name may fool you. This species, once on the brink of extirpation, now inhabits most of North America. Commonly found in wooded areas near bodies of water, the bald eagle patiently waits for prey. It feeds on fish, but can eat any meat it finds. Man has had adverse effects on their population, but slowly and surely, it has been recovering. As the top predator in its food chain, the bald eagle helps to control the population of other predators, and maintain balance in its ecosystem. The bald eagle is a warm-blooded vertebrate of the order of hawks and eagles. The genus to which it belongs is comprised of birds of prey, characterized by long wings. The name of its species comes from the Greek word for "white head". The bald eagle is found throughout all of the continental United States, Northern Mexico, and most of Canada. Eagles in frigid Northern areas migrate to unfrozen bodies of water during the winter, whereas those in more temperate climates have no need for migration. Since fish comprise a major part of the bald eagle's diet, it lives close to bodies of water. However, it also requires forested areas for perching and nesting, preferably with mature trees and low canopy cover. When waiting for prey on tall trees, it uses its superior eyesight to spot targets. The bald eagle has large wings, which aid it in hunting and which assist it in attacking its prey. Its powerful talons are also crucial to its hunting process, enabling the eagle to grab the fish out of the water. However, if the fish is too heavy, the eagle may be dragged into the water and could die of hypothermia. Most of the bald eagle's diet consists of fish, but it can eat almost anything. Other prey can include mammals, such as rabbits and deer, or small birds like ducks and geese. Rare attacks on great blue herons and swans have also been recorded. During the winter, when food is not as abundant, the bald eagle acts as a scavenger, feeding on carcasses as large as that of a whale. Occasionally, the bald eagle may also scavenge food remnants from camp sites and garbage dumps. An aggressive predator, the bald eagle competes with, and sometimes displaces, other carnivores high up in the food chain, such as coyotes and foxes. Bald eagles reach sexual maturity at the age of four or five, when they return to their birthplace to look for a mate. They usually mate for life, unless the other dies, or if multiple breeding attempts are unsuccessful. Mating and courtship consist of elaborate calls and flight displays On average, two eggs are produced each year, with the male and female alternately incubating the eggs while the other hunts for food. Unfortunately, it is rare for all of the chicks to survive. Nature's Wonders will continue after these messages...