迁徙英语怎么说
One compensation for not hibernating is the built-in urge to migrate.
However, when the lemmings' food supply becomes too low to support the population, a singular migration commences.
There are a few quarters left for species to migrate through without help.
Some birds migrate by flying to a warmer place for the winter, where they can find more food.
There are three main ways that animals survive the cold in winter: sleep, adapt or migrate.
Salmon also carry dangerous chemicals as the fish migrate between rivers and the sea.
One compensation for not hibernating is the built-in urge to migrate.
What about birds that migrate at night?
There are, of course, animal species that require large areas of habitat, and some migrate over very long distances.
Sami herders follow the migrations of the reindeer as they move across northern Russia to cooler areas during the summer months.
Unfortunately, this explanation fails to explain the hidden locations, unless the migrations were celebrated with secret ceremonies.
His definition is more intricate than Berger's, citing those five features that distinguish migration from other forms of movement.
Why did the near extinction and migrations of wild animals occur?
Animal migration, however it is defined, is far more than just the movement of animals.
When the planetarium sky matched the sky outside, the birds fluttered in the direction of their normal migration.
They prevent fish migrations and change aquatic habitats essential for native species.
Dates given for the migrations should nevertheless be treated with caution, except where supported by hard archaeological evidence.
He has analyzed clamshells to gain perspective on the Vikings, who migrated from Europe's mainland to Iceland, Greenland, and northeastern stretches of north America hundreds of years before Columbus.
And when game moved out of the lowlands in early spring, the expedition decided to return east rather than face possible starvation.
Migrating birds filled the pale sky.
Swallows migrate south in winter.
He noticed that as they fluttered around in the cage, they often launched themselves in the direction of their normal migratory route.
Most birds have to fly long distances to migrate.
Arctic terns, being true long-distance migrants, they nest in coastal wetlands of northern Europe but fly south for thousands of miles to spend the European winters in Antarctica.
During cooling most migrants would be expected to travel toward Africa, which is near the equator, since this is the direction dictated by habitat changes on a cooling Earth.