Placeholder Image

字幕列表 影片播放

  • [music]

  • Hi there.

  • I was just looking at my Texas Coastal Birding Trail map.

  • Did you know that the Texas coast is one of the hot spots

  • for birding in the whole country?

  • Every year, hundreds of millions of birds

  • migrate through Texas.

  • And if you stop to think about it,

  • migration is one of the real mysteries of nature.

  • For example, the ruby-throated hummingbird may fly

  • 600 miles, 26 hours, non-stop across the Gulf of Mexico

  • and end up in the same place each year.

  • How do they stay on course and manage such long flights?

  • Some studies have shown that hummingbirds and hawks

  • travel by day, using the sun, rivers, mountain ranges

  • and coastlines to guide them.

  • Songbirds migrate by night,

  • using the stars and the earth’s magnetic field as a compass.

  • Now how birds sense this magnetism is still a mystery.

  • Possibly it’s the tiny mineral crystals in their heads

  • that help them navigate.

  • Making these long journeys is dangerous.

  • Less than half the birds that start out make it back.

  • So birds have developed different adaptations

  • to help them navigate.

  • Some birds wait for tailwinds

  • and select the best altitude to help them fly.

  • Hawks hop thermals to save energy.

  • They fly in an upward spiral

  • on warm wind tunnels calledthermals.”

  • Once at the top, they glide to the next thermal.

  • Geese fly in a V-shape to reduce wind resistance

  • on the flock.

  • Songbirds depend on cooler evening temperatures

  • to prevent overheating.

  • And hummingbirds almost double their weight

  • with stores of fat to provide energy for their long flight.

  • Migrating birds depend on good habitat all along the way

  • to rest and eat.

  • People from all over the world gather at these prime

  • birdwatching areas.

  • It's a keen reminder that we must maintain good habitat,

  • especially wetlands, for both resident and migrating birds.

  • We still have a lot to learn about the mystery

  • of bird migration.

  • Hey, maybe calling someone a birdbrain

  • is actually a compliment!

  • [music]

[music]

字幕與單字

單字即點即查 點擊單字可以查詢單字解釋

B2 中高級

鳥類遷徙 - 德州公園和野生動物[官方] - 德州公園和野生動物[官方 (Bird Migration - Texas Parks and Wildlife [Official])

  • 1930 89
    Mark Lin 發佈於 2021 年 01 月 14 日
影片單字