Island retreat saves declining bulbul
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Trapping for the songbird trade has almost wiped out the Asian Straw-headed Bulbul, but a new study has discovered that the bird is thriving on a tiny Singaporean island.
Straw-headed Bulbul perhaps isn’t much to look at (at least compared to some other South-East Asian species), but no-one can deny it has a great song. Unfortunately, it’s this same rich, powerful melody which is threatening to silence the species forever.
Keeping passerines as pets is an integral part of South-East Asian culture; in Indonesia in particular, streets are lined with cages and songbird contests are big business. But as the streets grow louder, forests are falling silent as the widespread trapping of wild birds to meet demand for local markets is driving many endemic species towards extinction, with the prized Straw-headed Bulbul one of the more badly affected.
“Across much of South-East Asia, Straw-headed Bulbul has been relentlessly trapped from the wild to be later sold in the bird markets of Java, Kalimantan, Sumatra and Peninsular Malaysia,” says Yong Ding Li from The Australian National University. “The bird has gone extinct from Thailand and most parts of Indonesia where it used to be found, including the whole island of Java. Its populations have also collapsed across Malaysia.” The species is now in danger of disappearing forever. However, there is one small haven where the Straw-headed Bulbul’s presence isn’t just stable, but actually growing stronger: Singapore.
According to findings from a recent study led by Ding Li and published in the journal Bird Conservation International, wild populations of the species have steadily risen in Singapore over the last couple of decades and the country is now something of a global stronghold. Indeed, Singapore might now harbour more Straw-headed Bulbuls than anywhere else on the planet.
The authors from The Australian National University and Nature Society (BirdLife in Singapore) gathered data from more than 15 years of the Annual Bird Census, a yearly bird survey organised by Nature Society, and noticed the isolated increase.
The good news was not noted on mainland Singapore, however, where populations merely remained stable – although given the Straw-headed Bulbul’s plight elsewhere, even this is a win. Rather, the increases were documented on the small island of Pulau Ubin, situated north-east of mainland Singapore and one of the country’s last remaining rural areas. Here, the species’ population increased by nearly four per cent a year. Consequently, the tiny nation may now hold over a third of the world's population of this endangered species.
At a conservative estimate, Singapore is home to at least 200 individuals today. Furthermore, new sites have been discovered very recently, so with global estimates ranging from 600-1,700 individuals and trending downwards, Singapore could be harbouring over a third of the world’s remaining Straw-headed Bulbuls. On mainland Singapore, the bulbul persists in pockets of woodland such as Bukit Brown cemetery and Khatib Bongsu, both of which aren’t part of the current reserve network.
“More should be done to protect such places which are currently outside the existing reserve network,” said co-author Dr Ho Hua Chew from the Nature Society (Singapore), who is also vice-chair of its conservation committee. “Other biodiversity could also benefit from the conservation actions targeting the bulbul.”
The study offers further evidence of the value of citizen science. Without the hard work of volunteers, conservationists on the island would lack the data to determine which habitats are most vital for rare species such as the Straw-headed Bulbul, which has declined so dramatically in recent years that BirdLife uplisted its threat status from Vulnerable to Endangered in the 2016 Red List.
“Citizen science efforts to monitor wild bird populations in Singapore, including the Straw-headed Bulbul, have been led by the Nature Society’s Bird Group since 1986,” says co-author Lim Kim Seng, coordinator of the Annual Bird Census. “On a predetermined morning, scores of enthusiastic members will sacrifice sleep to be out in the wild at their assigned sites, counting birds for the census. Over the last two decades, these censuses have allowed us to track population trends of threatened species such as the globally endangered Straw-headed Bulbul.”
So while Thailand and parts of Indonesia may already have lost the species, at least in one small corner of South-East Asia, Straw-headed Bulbul can still be heard loud and proud.
Reference
Yong, D, Lim, K, Lim, K, Tan, T, Teo, S, and Ho, H. 2017. Significance of the globally threatened Straw-headed Bulbul Pycnonotus zeylanicus populations in Singapore: A last straw for the species? Bird Conservation International. doi:10.1017/S0959270917000028.
Straw-headed Bulbul perhaps isn’t much to look at (at least compared to some other South-East Asian species), but no-one can deny it has a great song. Unfortunately, it’s this same rich, powerful melody which is threatening to silence the species forever.
Keeping passerines as pets is an integral part of South-East Asian culture; in Indonesia in particular, streets are lined with cages and songbird contests are big business. But as the streets grow louder, forests are falling silent as the widespread trapping of wild birds to meet demand for local markets is driving many endemic species towards extinction, with the prized Straw-headed Bulbul one of the more badly affected.
“Across much of South-East Asia, Straw-headed Bulbul has been relentlessly trapped from the wild to be later sold in the bird markets of Java, Kalimantan, Sumatra and Peninsular Malaysia,” says Yong Ding Li from The Australian National University. “The bird has gone extinct from Thailand and most parts of Indonesia where it used to be found, including the whole island of Java. Its populations have also collapsed across Malaysia.” The species is now in danger of disappearing forever. However, there is one small haven where the Straw-headed Bulbul’s presence isn’t just stable, but actually growing stronger: Singapore.
According to findings from a recent study led by Ding Li and published in the journal Bird Conservation International, wild populations of the species have steadily risen in Singapore over the last couple of decades and the country is now something of a global stronghold. Indeed, Singapore might now harbour more Straw-headed Bulbuls than anywhere else on the planet.
The authors from The Australian National University and Nature Society (BirdLife in Singapore) gathered data from more than 15 years of the Annual Bird Census, a yearly bird survey organised by Nature Society, and noticed the isolated increase.
The good news was not noted on mainland Singapore, however, where populations merely remained stable – although given the Straw-headed Bulbul’s plight elsewhere, even this is a win. Rather, the increases were documented on the small island of Pulau Ubin, situated north-east of mainland Singapore and one of the country’s last remaining rural areas. Here, the species’ population increased by nearly four per cent a year. Consequently, the tiny nation may now hold over a third of the world's population of this endangered species.
At a conservative estimate, Singapore is home to at least 200 individuals today. Furthermore, new sites have been discovered very recently, so with global estimates ranging from 600-1,700 individuals and trending downwards, Singapore could be harbouring over a third of the world’s remaining Straw-headed Bulbuls. On mainland Singapore, the bulbul persists in pockets of woodland such as Bukit Brown cemetery and Khatib Bongsu, both of which aren’t part of the current reserve network.
“More should be done to protect such places which are currently outside the existing reserve network,” said co-author Dr Ho Hua Chew from the Nature Society (Singapore), who is also vice-chair of its conservation committee. “Other biodiversity could also benefit from the conservation actions targeting the bulbul.”
The study offers further evidence of the value of citizen science. Without the hard work of volunteers, conservationists on the island would lack the data to determine which habitats are most vital for rare species such as the Straw-headed Bulbul, which has declined so dramatically in recent years that BirdLife uplisted its threat status from Vulnerable to Endangered in the 2016 Red List.
“Citizen science efforts to monitor wild bird populations in Singapore, including the Straw-headed Bulbul, have been led by the Nature Society’s Bird Group since 1986,” says co-author Lim Kim Seng, coordinator of the Annual Bird Census. “On a predetermined morning, scores of enthusiastic members will sacrifice sleep to be out in the wild at their assigned sites, counting birds for the census. Over the last two decades, these censuses have allowed us to track population trends of threatened species such as the globally endangered Straw-headed Bulbul.”
So while Thailand and parts of Indonesia may already have lost the species, at least in one small corner of South-East Asia, Straw-headed Bulbul can still be heard loud and proud.
Reference
Yong, D, Lim, K, Lim, K, Tan, T, Teo, S, and Ho, H. 2017. Significance of the globally threatened Straw-headed Bulbul Pycnonotus zeylanicus populations in Singapore: A last straw for the species? Bird Conservation International. doi:10.1017/S0959270917000028.
