by Meenakshi Advani Rai, ACIW Mumbai
Fly means “to soar through air; move through the air with wings,” the Old English fleogan: “to fly, take flight, rise into the air.” Migratory 
birds connect people, ecosystems, cultures, development and nations, offering an extraordinary opportunity for international collaboration. “They are symbols of peace and of an interconnected planet,” says Secretary-General António Guterres of the United Nations.
Migratory birds fly distances beyond human comprehension; the arrival and departure of migrants, covering ground continuously, is an intriguing phenomenon. They fly for up to eight days straight, covering hundreds and thousands of kilometers, some even up to 16,000 kms, twice a year. Some add layers of fat; others shrink the gizzard and other organs in preparation for flight – the equivalent of jettisoning excess cargo.
Taking advantage of wind patterns, some flap their wings continuously in the interim of 12 seconds while soaring; some sleep, with partial brain activity; others soar continuously. Usually they fly during the day, while many are nocturnal and able to detect polarized light, which many of the birds use for navigation at night. To find the best habitats available for feeding, breeding and raising their young, journeys are both long and short.
How many birds are migratory?
An estimated 19% of the world’s 9,856 extant bird species are migratory, including some 1,600 species of land and water birds. Migrating birds use the Earth’s magnetic field and a variety of navigational cues – the sun, landmarks and stars – to point themselves in the right direction. During the day they use landmarks such as mountains, rivers and coastlines to guide them, returning to the same sites year after year.
Though some fly short distances, the extreme migrators can cross many oceans and continents to reach nesting sites and seasonal food sources. Flyways typically follow mountain ranges or coastlines, and may take advantage of updrafts and other wind patterns, avoiding geographical barriers such as (in the case of land birds) large stretches of open water. Their flyways are along historic routes that are well established, shaped by geographical, ecological and even meteorological factors.
Regardless of distance, birds migrate to escape conditions that threaten their survival and make their perilous journeys which involve a wide range of threats. These include habitat loss and degradation caused by agricultural development and human coastal and infrastructure developments that result in obstructions to their migratory flyways.
Does climate change disrupt migration?
Scientists are discovering that climate change is causing disruptions to the ancient journeys of the migratory birds, impacting the timing of 
elements of their life cycle – migration, breeding and nesting – leaving the planet with almost one million bird species at risk of extinction. There is a growing mismatch between the date when birds arrive in their breeding territories and the peak dates for blooming plants, emerging insects, spiders, seeds and other resources that breeding birds and their chicks depend on. These changes are a result of discrepancies in global temperatures, their inconsistencies and fluctuations.
Land-use agricultural activities limit the quantity and quality of available habitats in non-breeding areas. Over-harvesting and destruction, particularly at key migration locations, result directly in habitat loss and degradation. Forest fragmentation in breeding areas, with deforestation in non-breeding areas, has contributed to the decline of migrants. Chances of increased competition for land space are escalating between migratory and non-migratory birds. Harvesting and land degradation, nest destruction, water pollutions, toxic pesticides and land pollution are the human-created threats.
Degradation and habitat loss of critical stopover sites for migratory birds can have a devastating effect on their survival chances and lead to defragmentation, reducing populations.
Increased pressure from global human infrastructure developments and artificial man-made structures such as wind turbines, cables, 
towers and masts, all of which cause collision and death of migratory birds, has posed a threat to over 350 species of migratory birds, especially those flying at night. Increased building of wind turbines in flight paths and near wetlands, and expanded powerlines near sites where birds congregate, have also resulted in high bird mortality rates.
Air pollution, modifications of natural systems – such as dams and wetland drainage – residential and commercial development, emerging diseases, hunting, shooting, trapping, poisoning, electrocution by power lines, deliberate destruction and disturbance during their breeding period have upset their entire cycle. City lights confuse nocturnal fliers.
Migratory birds are excellent indicators of the state of our environment, and they perform important ecological regulating services. They play a vital role in seed dispersion and flower pollination around the landscapes, as well as seed dispersal of crops for human and livestock consumption.
They visit and act as natural controls by regulating pests and reducing populations of insects that are potentially harmful to plants, such as caterpillars, weevils, cutworms, beetles and flies. This saves farmers money they would otherwise spend on pesticides and crop protection measures.
Sea birds can also produce guano, a substance considered to be one of nature’s best fertilizers. In the Quechan language, guano means “the droppings of sea birds." Resulting from a complex process that starts with living plants that are eaten by insects, which are then consumed by fish that are finally digested by birds, guano is deposited on the floors of caves, rocks or ground in large quantities around bird colonies.
Migratory birds in Ecotourism
The journey of migratory birds is also a source of pride for cultures worldwide. Ecotourism 
helps to conserve important habitats. A great diversity of bird-watching literature helps bird-watchers and interested lay people to explore the fascinating world of migratory birds.
This educates people about the importance of migratory birds and ecosystems. There is an industry that has developed around migratory birds. Thousands of bird-watchers travel to various places in the world to watch birds in the hope of glimpsing rare species. Considerable economic benefit is achieved by disbursing funds for travelling, accommodation and entrance fees. Also, the production of birding equipment such as binoculars and cameras is an important multi-million dollar industry.
Migratory birds are among the most powerful symbols of the need to protect biodiversity and ecosystems across and beyond national borders. Their annual odysseys – already epic in scope – are made more difficult every year as biodiversity declines, ecosystems are destroyed and land is degraded in every region of the world.
20 small ways to conserve birds
Environment for the Americas offers these tips:
- Put curtains on your windows to prevent bird collision.
- Keep your dogs and cats from approaching birds when outdoors.
- Put fresh water in your bird bath every day and clean your bird feeders to prevent disease.
- Don’t buy illegally caged birds; make certain that the breeder or pet store is reputable.
- Use cloth grocery bags and reusable bottles – avoid plastic to reduce plastic pollution and conserve resources.
- Recycle and make bird feeders from old dishes and plastic bottles.
- Recreate the habitat that once existed in your area and restore natural habitats in your community.
- Birds need space for feeding, nesting, and other daily activities, so approach them from a distance.
- Help keep people and pets away when fledglings are in the “not ready to fly” period and on the ground after they leave the nest.
- Driving slowly gives you more time to respond and avoid the killing of any bird.
- Buy bird-friendly products; for example, from shade coffee farms which imitate native forests.
- Plant native species, which provide food, nest sites and cover for birds.
- Talk to and teach your friends, or start a club in your community to talk about birds and their challenges.
- Find a local park, get outdoors and appreciate the bird habitat near your home.
- Invite a buddy and see if you can spot more birds together or take a friend bird-watching.
- Support or join a conservation organization to learn and contribute to protecting birds and preserving their habitat.
- Contact your local nature center, library or conservation organization to volunteer and help with data collection.
- Shrink your energy bill by switching off lights, which also helps prevent birds from colliding into the windows.
- Avoid the use of pesticides which have toxic effects on birds’ health and that of their growing embryos.
- Learn the federal and local hunting laws that protect sensitive areas and manage the harvest of birds.
SOURCES
All Photos, credit to unsplash.com
National Geographic Magazine 2018
Critically endangered Migratory birds
