Every year in the month of March, one of 【小题1】 world’s greatest wildlife migrations (迁徙)stops in central Nebraska. For a short time, sandhill cranes(沙丘鹤)fi1l the state's wide, flat fields. The land provides the birds 【小题2】  the perfect place to rest and eat.

Since several years ago, more and more people 【小题3】 ( discover) the migration. Visitors crowd into river blinds—special buildings that help keep the bird watchers 【小题4】( hide) themselves. They look through their cameras or telescopes in wonder.

The sandhill cranes are worth the trip. They are 【小题5】(general) a little over a meter tall. They have long legs and necks. Their wings stretch over two meters. Sandhill cranes have soft, grey feathers. They 【小题6】 (know ) for having a bright red area on the top of their heads.

The birds stop in Nebraska as they make their way from their winter homes in Mexico and some 【小题7】(south ) parts of the United States. The birds usually spend two to three 【小题8】 ( week ) at this place 【小题9】 they leave. They arrive in waves, at times as many as 400,000 in one day. They eat in the nearby fields and grass lands. Leftover grain, insects and small creatures give 【小题10】   (they) the energy they need as they continue their trip north, toward Canada and Siberia.