篇章結構 · 自然 · 建議 高二下 起
How Do Birds Find Their Way?
選項（有一句用不到）
- (A)Human activity has created new dangers along the way.
- (B)Those that fly at night, on the other hand, are able to find their direction by the stars.
- (C)There, they can find enough food to survive the cold months.
- (D)Some birds, such as penguins, cannot fly at all.
- (E)The answer is that birds do not depend on just one method.
How Do Birds Find Their Way?
Every autumn, millions of birds leave their summer homes and fly thousands of kilometers to warmer places. Then, in spring, they make the same long journey back, often returning to the very same area where they nested the year before.
How do they know where to go? Instead, they seem to rely on several different "tools" at the same time.
Some birds use the position of the sun during the day. Many species can also sense the earth's magnetic field, which works for them much like a built-in compass. Near the end of the journey, familiar landmarks such as rivers and coastlines help them find their exact destination.
Unfortunately, the modern world has made these journeys harder. Bright city lights can confuse birds that travel at night, causing them to fly off course or crash into tall buildings. Some cities now turn off unnecessary lights during migration seasons to help the birds pass safely.