Bird Migration: Scientific Answers


It is a very frequent question: why do birds migrate? Believe it or not this question has never received a convincing answer from scientists. Despite being at the center of naturalistic research since the dawn of time, we still don’t know why birds decide to take this difficult path.


It is a round trip in which the bird moves looking for an environment that is more similar to its conditions. Certain habitats in some seasons are in fact unfavorable for feeding and rearing the newborn chicks. Let’s try to see what the researchers’ answers are to explain this fascinating phenomenon. 

Migration, research

As we have mentioned, one of the most complex and difficult behaviors to decipher in nature is precisely that of migration . The bird undergoes a profound change, which involves a continuous physiological and morphological adaptation. 

In this way it takes advantage of all the environmental factors present on the globe, in particular those concerning the climate. However, the phenomenon also involves the cognitive field of animals, which are able to learn maps , as some biologists have recently discovered. 


Behind the migration we discover all the charm of the birds, which thanks to this journey put into practice all their extraordinary qualities, among which we also find the long-term memory , the numerous social interactions and the ability to maintain precise points of reference by looking at the Earth from above.


An example are the so-called white-crowned sparrows , which originally from Canada and Alaska, move to the United States and Mexico during the winter, where they can find fruits, seeds and grass on which to feed. 

Which species migrate?

Even if there are many birds that migrate , not all species decide to move from one stage to another. Most bird species make predictable migrations, this means that they move to the same location  every year at the same time.


Researchers call this type of movement ” obligated “, and this is precisely the case of the dog bunting , a black bird which, together with the white- tailed weevil and the greater sandpiper , moves every year to the same place, making a predictable journey. 

Other species instead move in migrations that we will call “ facultative ”. This means that from year to year they will move to different locations, and will rarely return to a place they have already been. 

Among the birds that prefer this type of migration we find the gray teal , the banded stilt , the pine siskin and the capogrosso owl 


A tiring journey

How much does migration cost in terms of energy ? Imagine flying for hours keeping the same distance between one bird and another, eating when it happens trying to keep the speed constant. The birds, to undertake this tiring journey , prepare themselves for many days by eating in order to accumulate a lot of fat in the body. 

Fortunately, some aspects of this behavior are predetermined : this means that the direction , the distance and the departure time are inherent in the animal which knows at the level of nature where it will have to go and when it will have to leave. Although it seems like a group behavior, for each bird migration is unique experience , which according to age requires different learning and challenges never faced before.

Are there any birds that don’t migrate?

We mentioned earlier that although many birds prefer to move from one part of the world to another, there are also species that decide not to migrate , the so-called ” permanent “. 

Why don’t these birds need to move? One of the most obvious answers is that of food. Researchers have found that there are birds that don’t need to find new food from another part of the world, because they have year-round resources available in the same place. Among these we mention the Mexican bullfinches , the anteaters and the gray partridges 

Because they move in groups

Among the most frequently asked questions when looking at the sky, there is no wondering why birds prefer to move in groups . We can frequently admire the wonderful choreographies that these animals perform as they move over long distances. 

The timing with which they whirl through the air is amazing, but why do they form certain types of shapes? One of the more plausible answers is to protect themselves from other predators . Traveling in a group , in fact, they can be more secure in defending themselves from the birds of prey that want to capture them. 

Birds move on at different times of the day. Each group decides when to leave and most of the time they get off the ground during the night , as it is cooler at this time of day and less energy is wasted. 

When it gets dark, the risk of encountering dangerous predators is also lower as it is more difficult to be noticed. Despite this, however, there are many species such as cranes or geese that prefer to migrate during the day, as we often see from the splendid documentaries that show these wonderful animals traveling to other borders.

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