When I was at Singapore’s wonderful (and, as more mangroves are cut down, increasingly important) Sungei Buloh Wetland Reserve a few days ago, I came across a Milky Stork Mycteria cinerea feeding quietly in a low-tide channel in the middle of the reserve. Like (I suspect) many readers of 10,000 Birds I knew very little about Milky Storks except that they were pretty rare in the wild, and that the birds seen at Sungei Buloh are all thought to be free-flying escapes (probably from the Singapore Zoo)*. Consequently I took some photos, admired what is undoubtedly an interesting and unusual bird, but when it moved away further up the channel I moved on too, looking for species I knew to be wild like Copper-throated Sunbird and Stork-billed Kingfisher…

However when I went online to learn a little more about the species, I was shocked to discover just how rare and range-restricted this stork really is and I thought the photos and the information I found were worth sharing. Much of what follows is adapted from the Milky Stork species page on the BirdLife International website.

The Milky Stork Mycteria cinerea occurs only in Cambodia, Peninsular Malaysia and the islands of Sumatra, Java, Bali, Sumbawa, Sulawesi and Buton, Indonesia. Its population is now estimated at less than 5,500 individuals and it’s listed as Vulnerable by BirdLife because it has undergone a rapid population decline. The majority that are left are in Indonesia, with less than 5,000 on Sumatra and c.400 in west Java. There are estimated to be c.10-20 pairs at Tonle Sap lake, Cambodia. Numbers have apparently declined, at least in parts of its range, with counts from Malaysia falling consistently from over 100 individuals in 1984, to less than 10 birds in 2005. Its status in Indonesia has received less study, but although good numbers can still be found at some sites in southern Sumatra there are reports that numbers have declined considerably.

Threats to the survival of the Milky Stork lie - as is almost inevitable - with us humans. Milky Storks are predominantly coastal residents in the mangrove forests (and adjacent, less saline, swamps) of Indonesia and Malaysia, and as been discussed many times on 10,000 Birds and elsewhere mangroves across the whole of Asia suffered hugely from clearance in the last decades of the 20th Century and the early part of this one - in particular for the farming of Tiger Prawns for export to the US and Europe.

In Indonesia, many tidal forests including mangroves are threatened by agricultural conversion and development schemes, particularly large-scale fish farms and tidal rice cultivation, logging and related disturbance; as a result, mangrove clearance has been rapid. Sadly hunting for food and trade also exerts a significant pressure throughout its range: in 1989, 40-50 birds were shipped to zoos across South-East Asia. In Malaysia persecution and disturbance at nesting colonies are thought to be the main threat, whilst in Cambodia, exploitation of waterbird eggs and chicks and snaring of adults, for food and trade, coupled with the increasing likelihood of conversion of flooded forest for agriculture, threaten the suspected Tonle Sap lake breeding colonies.

An unusual threat that may apparently impact on wild populations is hybridisation with other stork species such as the far commoner Painted Stork Mycteria leucocephala. Mixed breeding has been reported in the wild (eg on the Bird Ecology Study Group blog at http://besgroup.talfrynature.com/2007/09/13/milky-x-painted-stork-hybrid/) and dilution of the genetic purity of such a threatened species needs to be controlled.

* UPDATE:
I’m grateful to Kenneth Kee, one of Singapore’s leading local birders, who sent me further information on the Milky Storks at SWBR:

Hi Charlie,
I first saw the Milky Stork at Sungei Buloh way back in Sept 1998 when I was leading a birdwatching trip there. They are free flying birds from both the bird park and zoo. They are doing well and breeding but so far no record of them breeding outside these 2 places. Same scenario goes for the Cattle Egret here, where they are free flying from the bird park. This pose some problems for birdwatchers as we do not know whether they are genuine migrants or from the birdpark. Most of these free flying birds will fly out in the morning to feed and then return back to their “home” to roost for the night.

Cheers
Kenneth

The fact that the Storks are breeding here (which I didn’t know) does perhaps raise the intriguing possibility of a free-flying population building up in Singapore which may become globally important in the light of the dwindling number of birds at traditional breeding sites (in much the way, say, as the Mandarin Ducks in the south of England - which derive from escapes of course - are now seen as globally important).

If anyone has any further thoughts on this supposition I’d be glad to receive it…

Kenneth Kee has again commented on the Milky Storks at SWBR and my question about free-flying birds:

Very interesting suggestion you have since this is an endangered bird.

My personal view is that as long as this introduced bird does not pose any problem and compete with the native birds, that will be fine. Unfortunately, some of our introduced birds in Singapore has become a pest like the Javan Myna displacing our Common Myna and House Crow displacing our Large-billed Crow. I am also suspecting that the escapee White-crested Laughing-thrush maybe displacing some of our babblers, although no evidence has been gathered.

So it is a fine line drawn. I would prefer not to have any introduced species unless there is close monitoring, control and studies done. On a brighter note, I’ve been observing Milky Storks at Sungei Buloh for over 10 years and they usually feed among themselves without disturbing or threatening any of the local or migrant species.

All photos copyright Charlie Moores 2008

This post has been submitted to Bird Photography Weekly #11. Go check it out!