Why do some birds migrate thousands of miles?


Birds are known to migrate thousands of miles to breed and in search of food. Depending on the season and type of birds, the migration could be both short-run or long-run. Therefore, let us discuss why some birds migrate thousands of miles every year.

Why do birds migrate?

Birds move from areas that are running low on resources to areas that consist of increasing resources. The two primary reasons birds do this is to find a location for food and nesting. 

Birds that nest in the Northern Hemisphere tend to fly northward in the spring to take advantage of exploding insect populations, budding plants, and abundance of locations for nesting. As winters settle in and the production of insects drops, birds return to the south again. Then again, some birds will return, whereas others such as hummingbirds will stay back as they are able to withstand freezing temperatures as long as an adequate amount of food is available. 

Given the fact that on long and arduous journeys they have to expend must energy and encounter great dangers one wonders why some birds migrate thousands of miles. The reason is: birds must move about in search of food, and as soon as the supply is exhausted in one place, they must go to another where food is abundant.

Besides, in some regions like Europe and Eurasia seasonal climatic and ecological changes occur that may require the birds to move away if they are to survive. This is the most obvious and perhaps the most important advantage provided by migration. By flying hundreds and sometimes thousands of kilometers, birds can trade bitter cold and long nights of northern winters for the gentler warmth and sunlight of southern climates. Conversely, in the summer they can escape the scorching heat of the south and enjoy the long cool days of northlands. The evidence that migration achieves these benefits is found in the avian species of India. Out of 1,301 species, only 41 are endemic. The rest are migratory or seasonal visitors.

Types Of Migration

Migration is all about the distance traveled. It could be periodic or large-scale movements. Let us take a brief look at different types of migrating patterns.

Permanent residents do not migrate regardless of the changes in seasons. They are able to find adequate food supply all year around. Therefore, they prefer staying at the same location where they were born.

Short-Distance migrants cover only a short distance. Most often, they will return as the day ends, otherwise, they will simply move from higher to lower elevations in search of food or to lay eggs.

Medium-distance migrants will cover a distance that will span several states. These birds will neither fly too far nor too short. 

Long-distance migrants normally move from breeding locations existing in the United States and Canada to wintering grounds in South and Central America. There are more than 350 species of North American birds that migrate every year. Depending on the type, the migration patterns will vary.

What triggers migration?

Migration could be triggered due to various reasons such as lower temperatures, changes in day length, and changes in food supplies. People who have caged migrating birds have noticed this often that when it is time to migrate, the birds will become restlessness. They will repeatedly flutter towards one side of their cage. The reason being that they are naturally programmed to fly away as soon as something triggers migrating behavior. 

How do birds navigate?

Birds are excellent navigators. They make use of the sun, stars, and, most importantly, the earth’s magnetic field to migrate. Such is the precision of the navigation that birds hardly become lost while flying. Different birds use different senses to help them navigate. Therefore, the secrets of their amazing navigation skills are not fully understood. In other cases, such as homing pigeons, there is evidence that the birds make use of their sense of smell. 

Concluding, birds primarily migrate thousands of miles in search of food. Some types, such as The Bar-tailed godwit, will fly for nearly 7,000 miles without taking a break. This is normally an eight-day journey during which the bird does not stop for food or rest, demonstrating astonishing endurance. And once the purpose is served, the birds return, and the process is repeated every year.

Additional reading:

Bird migration (Wikipedia)

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