Artificial Light has adverse Effects on Migrating Birds

The unavoidable light pollution of the city disrupts their flyways and is hazardous for them. The rising city’s artificial light is becoming one of the principal causes of migrating birds’ fatal collisions.

Almost 80 percent of the world’s population is covered under artificial light. While in Europe and North America the percentage is as good as 99 per cent. During the period from 2012 to 2016 through Satellite, it was found that artificial light in outdoor areas had increased by 2.2 % each year.

When the collective city light outshines like a constellation it disorients the passing migrating birds from their migration path. As it interferes with the light photoreceptor cell in the retina and obscures the magnetic compass of the birds. The confused birds get pulled toward the source of light and throng around it, and during the process majorly lose their energy reserves. As they come very close to the ground, either they become prey for housecats or collide with surrounding windows or buildings. 
Artificial lights are so harmful that it not only interferes with the migrating bird’s ability to navigate, but also disrupt their immune systems, microbiomes, foraging behaviour, and sleep cycles.

Artificial light at night (ALAN) causes Light pollution as it reaches into the airspace, and scatters light in the atmosphere. Over years it has increased so much that under these lights spread across the sky Milky Way is no longer visible clearly to Human eyes.
Not only migrating birds, but it has resulted in many medical health issues in humans also like breast cancer, reduced skeletal muscle, sleep disorders, gastrointestinal illness, mood swings, and cardiovascular disease.

Every year different species of birds come from different locations in the world. They cross 1000 km of distance to reach the best environmental conditions to nurture their entire community. Also looking for a habitat to breed and raise their young ones.  There are 10,000 bird species around the world, out of which approximately 1,800 are long-distance migrating species. In 2020, scientists had recorded the longest ever known migratory flight of more than 7,500 miles across the Pacific Ocean between Alaska and New Zealand for nonstop 11 days. 

In spite of so much research being conducted to date, it is not completely understood the pattern of the path followed by migrating birds.

The following pattern has been observed:

• Huge flocks of birds migrate to southern wintering areas from northern breeding grounds.
• Southern parts of Africa become a breeding ground for some birds while many migrate to northern wintering grounds.
• Some can be seen coming to tableland during winter and vice versa moving higher up to a lofty mountain in summer.

Many ancient Greek authors have mentioned in their books, the migration of bird species like storks, turtle doves, and swallows. Various migration patterns have been noticed. It is most commonly observed that migratory birds fly to regions with favourable breeding conditions, from the unsuitable climatic conditions that arise due to low temperatures. In fact, for centuries, in almost all cultures such arrival of migrating birds is believed to signify the beginning of spring and the rebirth of nature. That’s why traditionally these flocks of birds are considered a messenger of new birth or of peace and hope.