Spring bird migration: Risky journey in the skies

Travelling hundreds or thousands of kilometers between a bird's breeding and non-breeding habitats is a challenging, dangerous voyage that not all birds are able to complete. However, there are many reasons for birds to invade the skies every autumn and spring and migrate. 

Migratory birds

Migration is the regular movement of birds from one region of the earth to another and back again.

Species of birds known as migratory birds typically depart their breeding areas after the breeding season is over to spend the winter somewhere else before returning in the spring. These are frequently insectivores, like swallows or warblers, which are unable to obtain food in this area throughout the winter, according to Plantura Magazine.

On the other hand, “resident birds" are non-migratory birds that spend the entire year in their breeding grounds and accept whatever nature has to offer them. For instance, the spotted woodpecker, coal tit, and robin are natural resident birds in the UK.

Why do birds migrate?

According to the Spruce, food scarcity is one of the main reasons behind the migration of birds of all species. Food would grow scarce and breeding would be rare if all birds remained in the same regions year-round. However, millions of birds move to northern regions each spring to take advantage as the food supplies restock there. 

Birds also migrate for the sake of their families. They have developed various migration routes, schedules, and destinations over the course of millennia as they have spread out to breed. This increases the likelihood of producing healthy offspring by allowing birds to grow their young in a range of favorable environments. 

Birds' varied types of feathers have evolved over time to help them survive in various climates which have an impact on migration. When temperatures start to drop, for instance, many birds abandon their arctic nesting grounds for more temperate grounds. Similar to this, laying eggs further north in cooler places is desirable, because the hot tropical regions can be a tough environment for growing delicate chicks.

Diseases are another reason behind migration. Any large group of birds jammed in one habitat is vulnerable to parasites and diseases. Birds that move to various regions are less likely to infect their entire population, including their young, with a disease.

Migration types

There are different types of migrations depending on species and conditions. 

Short-distance migrants move only a short distance, typically from one elevation to another on a mountainside. Birds who travel for several hundred miles make a medium-distance migration. The wintering grounds of long-distance migrants are typically in Central and South America, while their breeding areas are in the United States and Canada. Almost 350 species of North American birds partake in long-distance migration, despite the difficult journeys required, All About Birds reported. 

How do birds navigate?

Researchers have always asked the question about how migratory birds find their way south. It was revealed that many species' migratory habits are instinctual, and even animals held in isolation are aware of their precise location.

There is a form of internal compass that enables birds to sense the inclination of the earth's magnetic field. Aside from familiar landmarks, birds can also use the stars and the sun's location as navigational aids. Birds' capacity to see UV light allows them to determine the latter even amid cloudy skies, according to Plantura Magazine.