MANY songbirds that fly south to Asia between November and February are under threat, and researchers calling for more global cooperation to protect them.
The birds routinely escape the winter in northern parts of the world, such as Siberia, for Asia's tropical areas, and use migratory routes collectively known as the East Asian- Australasian Flyway.
The flyway spans 37 countries from Arctic Russia and North America to Australia and New Zealand - an area of about 84.7 million sq km.
A group of researchers led by Singaporean bird scientist Yong Ding Li found that their habitats in these countries, such as forests and wetlands, are increasingly being depleted due to human developments.
The birds also face threats such as tall buildings, including those in Singapore, that lead to fatal collisions, and hunters who trade in ornamental birds.
Mr Yong, who is a graduate student at the Australian National University (ANU), said that unlike migratory shorebirds and waterbirds, which have been extensively studied due to their ability to spread diseases, there has been little research on songbird numbers.
But anecdotal observations by birdwatchers as well as scientific surveys suggest that many bird populations have been declining in the wild, some by as much as 70 per cent.
The researchers from ANU and Sun Yat Sen University in China reviewed reports by birdwatchers and other scientists in countries along the flyway.
They identified at least 254 songbird species that use the flyway.
Of these, 15 are listed by conservation group BirdLife International as threatened, seven as near-threatened, and 56 as having declining populations.
The list of threats included deforestation and degradation of temperate forests in Mongolia and eastern Russia due to logging, mining and fires; the draining of Canaba marsh for agriculture in central Luzon in the Philippines; the trapping of songbirds in Cambodia for religious reasons, such as "mercy releases", as well as their trapping and sale as pets in Indonesia.
Hunting of wild birds for food in rural areas and the pet trade remains rampant across South-east Asia, the researchers said.
Songbirds migrating at night are also strongly attracted to artificial light.
Some of Asia's largest cities are extensively lit at night and have many high buildings, especially in Shanghai, Guangzhou, Hong Kong, Hanoi, Bangkok and Singapore, and this may have led to many bird deaths.
The researchers said that more international cooperation, conservation of key habitats and monitoring and research are needed to protect the birds.
Mr Yong said that, for Singapore, "most people associate migratory birds with Sungei Buloh, but most of the birds - and the vast majority are songbirds - are found across the country".
He added: "Their conservation needs to extend beyond nature reserves, to little remnants of habitats outside the reserves, including small patches of woodland like Bidadari."
Songbirds under threat
Flies from China to Sumatra, Indonesia, stopping in Singapore along the way in September for two weeks to a month.
Can be seen in Bidadari every October.
Population decline observed by birdwatchers in China.
Threats include loss of its natural forest habitat due to logging and agriculture in countries along its flight path.
Some fly from different parts of South-east Asia, such as Vietnam and Thailand, to Sumatra. Others stay put.
Commonly killed in collisions with buildings, especially in Singapore.
Believed to migrate from eastern Russia and Hokkaido, Japan, to southern China and parts of South-east Asia between August and October.
Population estimated to have fallen by at least 70 per cent in Russia between 2000 and 2010.
Threats include being trapped, cooked and sold as food in Sanshui city and Guangdong in China. The birds are also stuffed and sold as mascots in China as their presence in homes is believed to confer happiness. In Cambodia, they are often trapped for "merit release", a religious ritual.
Additional reporting by Carolyn Khew
This article was first published on Feb 21, 2015.
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