One of the most spectacular migrations on the planet is now under way, and Hong Kong, as it has been for centuries, is at its heart. While not as breathtaking as the running of the great wildebeests on the Serengeti, the mass movement of Asia's migratory waterbirds is nonetheless astonishing in scale and rich in biological significance. The birds travel on what is called the "East Asian-Australasian Flyway", one of the world's most important waterbird routes. It spans 13,000 kilometres and involves over 50 million birds.
Here in our backyard, the areas of Mai Po and Inner Deep Bay, a tiny nature reserve squeezed between two of Asia's most densely populated cities, forms a critical link in this winged migration, a biological process that repeats itself every year.
Conservative estimates have around 120,000 migratory waterbirds passing through Mai Po each year, according to WWF-Hong Kong, which has a contract to manage the site that has been designated for international protection under the Ramsar wetland convention since 1995. Roughly 90,000 of these birds winter here, with over 30 species classified as being of global conservation concern.
The birds are drawn to the area by its lush marshes, intertidal mudflats and fish ponds, which form a winter oasis for rest and rejuvenation before they head north to their breeding grounds in China, Mongolia and Siberia. Thousands of ducks, gulls and the famous black-faced spoonbill typically arrive at Mai Po between late October and December and remain until March or April.
But the future of these precious wetlands is in doubt, as threats of habitat loss, degradation and fragmentation grow. The culprits are development and land management practices that are destroying the wetlands' traditional fish ponds.
Of the 2,000-hectare wetland area, the Ramsar treaty protects only about 75 per cent. The ecological value of the other 25 per cent, set up as buffer zones to protect the designated site, is now slowly deteriorating due to ineffective land-use policies. Clearly, much more should be done to preserve this Hong Kong treasure.
Currently, a hodgepodge of international treaty protection, local environmental ordinances and town planning guidelines substitutes for the government's lack of a comprehensive conservation policy. Such a policy would take account of the cumulative effects of habitat loss in Hong Kong, rather than the current piecemeal approach, which has been likened to a death by a thousand cuts. And more cuts may be on the way.
Non-governmental organisations and conservationists are keeping a watchful eye on several development proposals in the protected area or just outside it in the Lok Ma Chau Loop and those under the government's public-private partnership scheme, such as Nam Sang Wai, a popular spot for outdoor wedding photos and birdwatching. That scheme allows developers to build on small parcels in exchange for protecting larger chunks of habitat.
While any development on those sites could be a way off, loss of habitat is already a daily affair out on the wetlands. It's as if a war were being waged on the birds. But the birds are just the collateral damage. The real targets are the fish ponds.
In Hong Kong, traditional fish ponds, which have long been part of the local culture, are supported by rich vegetation and form a valuable part of the wetland ecosystem. What concerns conservationists is that they are fast disappearing in and around the Ramsar site in Mai Po, being replaced by intensive, industrial-scale ponds that denude the natural habitat and are of low ecological value. In parts of the wetlands, these eyesores dot the landscape as far as the eye can see. Waterbirds, once a common sight on the ponds, are now largely absent - a telltale sign the ecosystem is in decline.
And as more wetlands in the rest of Asia are lost, Mai Po's importance only grows. The site offers profound lessons for the entire region, particularly on the mainland, where many wetlands are virtual deserts, their fauna decimated by aquaculture and the hunting of wild birds for food. With little research on the loss of waterbirds in Asia, Mai Po's role as a centre for collecting data and cataloguing waterbirds takes on added significance, not least of which relates to human health.
The ongoing outbreak of the H7N9 virus reminds us of what biologists have known for a long time - that wetland sanctuaries serve as a critical front line against avian flu. A report commissioned by the UN Environment Programme recommended years ago that countries preserve their wetlands as an important preventive to keep migratory birds from mixing with domestic fowl. Wetlands such as Mai Po create such a natural protection zone, one that makes possible the harmonious co-existence between humans and wild birds.
Not all is bad news, however. The Convention on Biological Diversity will take effect in Hong Kong next year, and with it comes a new level of government responsibility to protect the biodiversity, including wetlands and their rich wildlife. Green groups are already working closely with the government on ways to maximise the convention's impact here.
To meet its new international obligations, the government should ramp up tools already at its disposal. Of these, the public-private partnership scheme seems to be the most viable at present.
Another proposal, being pushed by green groups, is land swaps, which protect critical habitat in exchange for land to build elsewhere.
As the world celebrates World Migratory Bird Day next month, the people of Hong Kong have much to be proud of in the city's role in preserving this critical piece of the region's fragile ecosystem. It would be nice if the government also did its part.
Martin Murphy is a former US diplomat. He covered global environmental issues for the State Department for over 20 years