The regular seasonal movement of birds is called "bird migration". Birds travel tens of thousands of miles to find the ideal environments for feeding, breeding, and nurturing their young. Utilizing the longer days of the northern summer for reproducing, feeding their young, and avoiding harsh winters is the main goal of migration. However, birds will eventually return to their original place at the end of the term. Siberian Crane (also known as snow cranes), Greater Flamingo, and Artic tern are the most common migratory birds. The Arctic ern, which annually migrates between its Arctic nesting grounds and the Antarctic, holds the record for the longest bird migration. This article will explain Bird’s Migration which will be helpful in preparing the Environment Syllabus for the UPSC Civil Service exam.

Why do Birds Migrate?

• Birds migrate in order to move from low-resource areas to high-resource areas or vice versa.
• Food and nesting places are the two main commodities sought after.
• Birds that breed in the Northern Hemisphere typically move northward in the spring to take advantage of the abundance of nesting sites, expanding insect populations, and blossoming plants.
• The birds once more migrate south as winter draws near and the number of insects and other food sources decreases.
• Escape from the cold is a driving force, but many species, like hummingbirds, can tolerate subfreezing temperatures if they have access to enough food.

What are Migratory Species?

• The term "migratory species" refers to any species or lower taxon of wild animals whose population, or any geographically distinct portion of its population, regularly and predictably crosses one or more national jurisdictional lines.
• For some migratory birds and mammals, the distance traveled between habitats can occasionally surpass thousands of miles or kilometers.
• A migratory path may involve nesting and necessitate the presence of habitats both before and following each movement.
• Various concerns, such as habitat loss in breeding sites, increased hunting along migration routes, and degradation of their feeding grounds, make migratory animals particularly vulnerable.
• Governments ratified the 1979 Convention on the Conservation of Migratory Species (CMS) of Wild Animals as a consequence of global concern over these dangers.

Bird’s Migration - Types

The type of migration that particular migratory birds adopt can be determined by the following:

• Seasonal Migration: It takes place as the seasons change. When a location's harsh conditions make it impossible for them to exist, birds migrate away from there.
• Latitudinal or Longitudinal Migration: This type of migration takes place between various longitudinal or latitudinal sites, either from North to South, from East to West, or both.
• Altitudinal Migration: It typically occurs for birds that give birth in high-altitude regions and must migrate again due to the difficult conditions there.
• Loop Migration: Birds that migrate in this way typically do so annually in cycles to make use of the resources in two different places.
• Nomadic Migration: They remain in one spot until there are enough resources, after which they migrate because it is difficult to understand their precise patterns and timings.
• LeapFrog Migration: It's a form of skip migration where birds travel great distances to avoid a sedentary population.
• Reverse Migration: When birds are confused, they may pick an unexpected course or fly in the opposite direction.

Bird’s Migration - Features

• Migratory birds have appropriate morphological and significant physiological characteristics.
• These characteristics enable these birds to migrate between sedentary and migratory lifestyles, as well as to choose the optimal way and time.
• During the resting times in between migrations, these birds have a tendency to overstock on energy reserves like lipids.
• The trigger for migration is also influenced by environmental factors, including changes in day length, and is controlled by genetic and physiological factors.
• Numerous authors have also provided documentation of the scientific basis and important elements particular to migratory birds.
• These birds have the ability to fly at a range of speeds and altitudes.
• Some birds fly at low altitudes within the range of human vision, while others fly at high altitudes.
• For instance, songbirds travel at 500–2000 feet in the air, whereas geese or vultures once flew at 29,000–37,000 feet.

Bird’s Migration - Adaptation

• To adapt to the demands of migration, birds must change their metabolism.
• In nocturnal migrants, specific physiological adaptations are needed for energy storage through fat deposition and sleep regulation.
• In addition, a bird's feathers need to be molted (shedding) because of wear and tear.
• This molt occurs once or twice a year, but the timing varies depending on the species, with some molting before leaving for their mating grounds and others molting before heading there.
• In addition to physiological adaptations, migration occasionally necessitates behavioral modifications, such as flocking to save energy or lower the risk of predation.

Migratory Birds of India

• There are between 1500 and 4000 bird species that are known to migrate.
• Out of the roughly 2000 species and subspecies found in India and South Asia, about 350 are migrant species.
• Over 100 different kinds of migratory birds are known to have flown into India, either in search of food or to avoid the harsh winters in their home countries.
• Winter migrants make up the majority of migratory birds on the Indian subcontinent.
• Among these, Amur falcons, Bar-headed geese, and Black-necked cranes are notable species.
• The Central Asian Flyway (CAF), which spans regions between the Arctic and Indian Oceans, includes the Indian subcontinent as part of its extensive network of bird migration routes.
• Since India is a signatory to the Convention on Migratory Species (CMS), it has also created the National Action Plan for the Conservation of Migratory Species in the Central Asian Flyway.

Migratory Birds of India - Threats

• Loss of biodiversity: The loss of biodiversity is a result of overexploitation, unsustainable use of natural resources, population explosion, increased weather variability, and climate change.
• Illegal killing: Hunting along migratory bird species' pathways endangers some of them.
• Stopover Habitat Loss: During their migration, migratory birds stop at stopping locations to eat, rest, and refuel. However, overexploitation and growing urbanization have put many rest areas in danger.
• Collision: Migratory birds have also been impacted by structures like power lines, wind turbines, and offshore oil rigs.
• Poisoning by Pesticides: Pesticides have a negative impact on migrating birds as they have the potential to directly kill some species.
• Increasing Illumination: By confusing the birds, artificial nighttime lighting has a negative impact on migration.
• Increasing Encroachment: Birds can starve to death due to lack of food, growing human intervention, and encroachment.

Migratory Birds of India - Steps to be Taken

• Long-term monitoring studies to evaluate bird movement patterns, illness surveillance, and population counts
• Spreading the knowledge about bird migration and its effects. enlisting community support for migratory birds nesting and conservation
• During the migration season, fishing operations should be reduced, abandoned, or prohibited.
• To encourage birds to roost and establish their nests, it is necessary to maintain natural habitats and provide bird-friendly landscaping.
• Prohibiting single-use plastics and preventing their disposal in water sources.
• In order to help the conservation of migrating birds, strict law enforcement is necessary.
• In regions where birds congregate, modern technologies like drones can be utilized to trace poachers.
• Reducing nighttime lighting along the migration routes.
• Increasing public awareness of the need to maintain migratory birds' natural habitats and practice conservation.

Convention On The Conservation Of Migratory Species (CMS)

• The Convention on the Conservation of Migratory Species of Wild Animals, generally known as the Bonn Convention or CMS, is an intergovernmental agreement signed under the auspices of the United Nations Environment Programme.
• It focuses on the conservation of wildlife and ecosystems on a global scale.
• It is the only convention that addresses removing or harvesting wild species.
• 173 migratory species from all over the world are currently protected by the Bonn Convention.
• The Central African Republic ratified the Bonn Convention on September 1, 2020, making it the most recent nation to do so.

*To know more about the topic, click this link Convention On The Conservation Of Migratory Species

Conclusion

The phenomenon of bird migration is crucial to the survival and reproduction of several bird species. Additionally, these birds have inherited behavioral and physiological traits that are appropriate for their migratory lifestyle. The route that these birds take is both predetermined and preset. Since ancient times, migratory bird movements have been tracked for their cultural significance and to forecast annual seasonal changes. This demonstrates the exactness and precision of the behavior these birds exhibit while migrating. We must now look for conservative measures to conserve this amazing population of migrating birds in light of growing human influence.

FAQs

MCQs

1. What primarily drives bird migration?

A) Reproductive success
B) Climate change
C) Seasonal changes in food availability
D) Nesting habits

2. Which of the following is an example of partial migration?

A) All individuals of a species moving south for winter
B) Some geese migrating while others remain
C) Birds moving up and down mountains
D) Irregular movement based on food availability

3. Which factor does NOT influence bird migration?

A) Climate
B) Food availability
C) Age of the bird
D) Color of feathers

4. Which type of migration is characterized by movement based on unpredictable food sources?

A) Complete migration
B) Nomadic migration
C) Partial migration
D) Altitudinal migration

5. How do birds contribute to ecosystems during migration?

A) By nesting
B) By pollination and seed dispersal
C) By avoiding predators
D) By creating new habitats

GS Mains Questions and Model Answers

Q1: Examine the ecological importance of bird migration in maintaining biodiversity.

Answer: Bird migration plays a crucial role in maintaining biodiversity by facilitating gene flow between populations, enabling species to adapt to changing environmental conditions. Migratory birds contribute to the ecological balance through their roles as pollinators, seed dispersers, and predators of pest species. By connecting various ecosystems, migratory birds enhance genetic diversity, which is essential for resilience against environmental changes. Furthermore, they support nutrient cycling, as their migration patterns often coincide with seasonal changes that affect ecosystem productivity. Protecting migratory routes and habitats is vital for preserving biodiversity and ensuring the health of ecosystems worldwide.

Q2: Discuss the impacts of climate change on migratory patterns of birds.

Answer: Climate change significantly impacts migratory patterns of birds by altering seasonal weather conditions, leading to mismatches in timing between migration, breeding, and food availability. As temperatures rise, some migratory species may arrive at breeding grounds earlier than usual, while food sources may not yet be abundant, affecting reproductive success. Additionally, changing climatic conditions can shift traditional migratory routes, leading to habitat loss or increased competition for resources in new areas. These disruptions can threaten the survival of migratory species and may lead to declines in populations, underscoring the urgent need for climate action and habitat conservation.

Q3: Analyze the challenges faced by migratory birds in urban environments.

Answer: Migratory birds face numerous challenges in urban environments, where habitat destruction and fragmentation can severely impact their migratory routes and stopover sites. Urban areas often present barriers such as tall buildings, traffic, and pollution, which can lead to increased mortality rates. Additionally, the presence of artificial light can disorient nocturnal migrants, causing them to collide with structures or veer off their migratory paths. Habitat loss due to urban development reduces the availability of food and nesting sites, further exacerbating the struggles of migratory birds. Conservation efforts that focus on creating green spaces, preserving natural habitats, and reducing light pollution are essential to support migratory birds in increasingly urbanized landscapes.

Previous Year Questions on Bird Migration

1. UPSC CSE Prelims 2021:

Question: Which of the following factors primarily influences bird migration?

A) Habitat availability
B) Climate change
C) Food resources
D) Nesting habits

Answer: (C)

Explanation: Food resources primarily influence bird migration, as birds move to areas with abundant food during specific seasons.

2. UPSC CSE Mains 2019 (GS Paper 1):

Question: "Evaluate the role of migratory birds in ecosystem functioning." Discuss the ecological consequences of changing migratory patterns.

Answer: Migratory birds play a vital role in ecosystem functioning by facilitating pollination, seed dispersal, and pest control. Their movement between ecosystems contributes to nutrient cycling and helps maintain ecological balance. Changes in migratory patterns due to climate change can have significant ecological consequences, including altered breeding success, reduced plant diversity, and shifts in predator-prey dynamics. As migratory birds adapt to new conditions, the interconnectedness of ecosystems may be disrupted, potentially leading to declines in both bird populations and the ecological services they provide. Understanding these dynamics is crucial for developing conservation strategies that support the resilience of both migratory species and their habitats.