BETWEEN September last year and April, at least 20 birds crashed into buildings in Singapore's central region, according to preliminary results of a study by the Nature Society (Singapore), or NSS.
This is the period when most migratory birds arrive and leave here each year.
In total, there were 47 collisions documented by the society's Bird Group.
The group said last month that birdwatchers had found an increasing number of dead or injured migratory birds in urban areas since the 1990s.
More than 100 species and thousands of birds pass through Singapore each year, including the blue-winged pitta and the large, wading whimbrel.
To understand the extent of such migratory bird collisions in Singapore, the Bird Group started a five-year survey last year to document these accidents.
It aims to identify bird species which are prone to crashing, where and when the accidents happen, and aspects of the urban landscape that may prove hazardous.
People can report such incidents through an online form.
The group also worked with an avian genetics laboratory at the National University of Singapore (NUS) which collected the dead birds.
The Bird Group found that the top three bird families affected were pittas, flycatchers and kingfishers.
Mr Albert Low, who authored the report, said: "These three families are predominantly nocturnal migrants. These birds may be especially vulnerable to collisions with lighted structures owing to the multitude of high-rise, intensely-lit housing and office blocks, which are a feature of Singapore's skyline."
The lights can distract the birds from cues they receive from the stars and moon.
The creatures could also crash into buildings because they are attracted to the light, or might circle the buildings until they become exhausted.
NUS Department of Biological Sciences research assistant David Tan said the glass on the buildings may be so reflective that it seems to be the sky.
He said one way to reduce such accidents is to put decals or louvres on the windows to make the buildings more visible to birds.
More research is needed to determine why such collisions happen, he added.
Singapore could also look to other countries. The city of Calgary in Canada, for example, has bird-friendly, voluntary guidelines for buildings, including using blinds to make clear glass more opaque or angling glass downwards so it does not reflect the sky.
In April, the government of New York in the United States announced that all of its state-owned and managed buildings will turn off non-essential outdoor lighting from 11pm to dawn during peak bird migration periods to reduce such collisions.
If you see an injured or dead bird that may have flown into a building, take photographs of it and go to www.tinyurl.com /sgbirdcrash.
This article was first published on June 2, 2015.
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