Information about birds – migration
Why do birds migrate?
Birds seek out places that have warmth, food and are safe for breeding.
During the long days of the northern summer, birds have more hours to feed their young on the abundant insect population. As the days shorten in the north in autumn and food supplies become scarce, the birds migrate south.
Where do birds go?
Many species migrate very long distances. It is very common that birds will migrate to the northern hemisphere in the summer where they can breed in a cooler climate. In the winter they will head to the southern hemisphere where the climate is more temperate. This pattern is known as a flyway.
When do birds migrate?
Each species migrates at a certain time of year and time of day. Some are very irregular in their migration patterns.
Some species start their migration south in early July and some don’t migrate until the weather gets too harsh or the food becomes unavailable later in the fall.
How do they keep going?
Some birds eat along their journey by finding food when they are hungry. But some birds eat more just before migration. They store a special, high-energy fat in their body to last them for several weeks as they migrate.
The Arctic Tern has the longest known migration route. It flies about 22,000 miles each year between its breeding grounds in the high Arctic and its winter grounds in the Antarctic.
How do birds find their way?
Navigation is complicated because it requires three things: birds must know their current location, their destination and the direction they must take to get there.
Some birds use the sun and the stars to navigate. Some also use landmarks like rivers, mountains or coastlines. Some might use smell. Still others might follow the other birds in the flock. Some even monitor the Earth’s magnetic field. These birds are able to use their visual system along with tiny grains of a mineral in their heads. This mineral, called magnetite, might act like a compass.
Not all is known about how birds find their way but they probably use more then one method.
How fast do birds fly?
Speed ranges from 20 to 50 miles per hour. Larger birds fly faster than smaller birds. If the flock flies for 10 hours a day, then they could fly about 400 miles a day!!!
How high do birds fly?
Radar studies show that most flight occurs at less than 10,000 feet, but some have been recorded flying at 27,000 feet!!
Birds on long-distance migrations fly at higher altitudes than short-distance migrants.
What are the dangers of migration?
Sometimes birds must fly across harsh habitats such as deserts, where there is little water, or oceans, where there is no place to land and little food to eat. Sometimes stormy weather may make the trip difficult. There can be many predators along the migration route.
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