Most bird species such as the songbird, waterfowl and shorebird migrate at night and primarily navigate with the help of moonlight and starlight. For these birds, migration is the toughest phase within the year as they may stumble upon circumstances that they may not have faced before or anticipated during their flights.

With the widespread use of excessive artificial lighting in cities, the luminescence from these light sources is extended to the airspace uninhabited by humans, resulting in skyglow (which I had mentioned previously). Thus, migration is made even more challenging as artificial lights can disorient migratory birds and affect their flight trajectories, a phenomenon known as fatal light attraction. As a result, they wander off course and collide into illuminated buildings and towers. In the United States alone, this phenomenon has led to the death of approximately 500 million to 1 billion birds annually! This worrying trend is not unique to just the United States.

Between 1998 and 2016 in Singapore, 237 migratory birds collided with buildings and 157 of them died. As Singapore is part of the East Asian-Australasian Flyway, between September to March every year, migratory birds from as far away as Siberia use Singapore as a resting point when travelling to Australia.

 

Below are a few examples of bird species – the blue-winged pitta, yellow-rumped flycatcher, western hooded pitta and oriental dwarf kingfisher –  which make up slightly more than half of all collisions as they fly at lower altitudes that make them more prone to building collisions at night.