Read the article below about migration among birds in North America. Find the main idea, 3 supporting details and summarize this article in 100-120 words.
Why Do Birds Migrate? The longer days and abundant food of the northern hemisphere summer provide greater opportunities for breeding birds to feed their young. The extended daylight hours and food resources allow birds to produce larger clutches than those of related non-migratory species remaining in the tropics year round. As the days shorten in autumn and the breeding period is over, the birds return to warmer regions where the available food supply varies little with the season. Many northern (North American) breeding ducks, geese, and swans are also migrants, but need to move from their northern breeding grounds only far enough south to escape frozen waters. The advantages of migration offset the high stress, physical exertion, and other risks of the migration. Day length is the primary environmental factor that prompts birds to prepare for migration. They have hormonal changes that increase their appetite and result in substantial weight gain, giving them the fat reserves that provide energy for their migratory flight. They also show increased activity at night, which is when most birds migrate. While length of day is the primary stimulus for migration, birds also respond to temperature changes. For example, if a spring is late and temperatures are colder than normal, birds delay migration; if spring is early, birds also begin migration early. The timing of the migratory cycle must allow birds to arrive on the breeding site so that there is time to establish a breeding territory, mate, incubate the eggs, and hatch the young before the optimum abundance of food is available to feed the young in the nest. Similarly, if birds waited until the climate in their northern breeding grounds became intolerable, there would be no time to gain the necessary weight that provides the energy surplus needed for their southbound migration.
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Kumudendu, 1275. Nachiraja, 1300. Ratta Kavi, 1300. Nagaraja, 1331. Noted Kannada poets and writers in the Seuna Yadava Kingdom.
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A summary of migration of birds
- many birds migrate due to increase in the amount of food in the warmer areas which is good for feeding the young birds.
- The increase amount of daylight it helps the birds to breathe more easily. hence the number of words can be increased by this process. in winter the availability of food in the cold areas become very less. In addition to this the rivers also freeze inse water is not available.
- The hormonal changes results in increase of appetite and hence causes the increase in the food that they consume that helps them to fly from one area to other. even at night they show a large amount of activity which helps the birds to migrate. If the spring appears late then this stay in the warmer areas for longer time.
To know more,
why is geography known as 'body of knowledge'? - Brainly.in
https://brainly.in/question/4460824
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