From the air we see that Kuantu, in northwestern Taiwan, is flanked to the northeast by the tall mountains of the Mt. Tatun group, and to the west by Mt. Kuan-yin and the Linkou plateau. These two massive windbreaks shield Kuantu from the force of the northeasterly monsoon.

On making landfall at the Tanshui Estuary, clever birds discover that although the beaches at Watsaiwei offer plenty of food, vegetation is sparse and they are exposed to the wild buffets of the north wind. The less hardy among them scout their way upriver until they come to the wetlands of Kuantu. Here they can shelter from the wind and cold and find a range of vegetation to roost in, and there is no lack of food. This makes Kuantu a prime choice as a place to replenish their energy before they spread their wings and continue on their way.

If you enter at the sluice gates in front of Kuantu Temple and set out along the Keelung River embankment, the 100-plus-hectare Kuantu wetland stretches out before your eyes. The large patch of luxuriant mangrove forest to the right, outside the embankment, is the Kuantu Nature Reserve, while the wetland area to the left, with its high and low tussocks of grass and pools large and small, is Kuantu Nature Park, which opened in late 2003.

However, 30-odd years ago, to both sides where the embankment now runs was an expanse of abandoned farmland that had become a marsh filled with reeds and sedges. Earlier still it was farmland made up of paddy fields. If we turn back the clock even further to 1697, when Yu Yonghe came to Taiwan to mine sulfur, as his boat sailed up the Tanshui River, flanked by mountains, on arriving at Kuantu he was amazed to see a huge lake--the fabled Taipei Lake!

The varied fortunes of Kuantu over the last three centuries and more tell of the changing ecology of the waters here. After the Kuantu narrows were dynamited in the 1960s to broaden the river by 100 meters, the tides brought seawater flowing into this riverside wetland a full ten kilometers from the river mouth. With the saltwater came the mangrove species Kandelia obovata, which replaced the grassy marsh outside the embankment. Thus a diverse wetland environment came into being, with saltwater, brackish and freshwater areas.

Ubiquitous marshes and ponds in the Kuantu Nature Reserve in Taipei create an idyllic scene. In early spring as winter draws to a close, birds flit among the gentle waves, as if right out of a poem or picture.

A forest in the water

Today, when the tide rises, seawater floods the swamp outside the embankment, covering the roots of the mangroves so that the trees seem to grow out of the water, while at low tide the mud teems with shrimps, crabs and mudskippers, and shorebirds and waders fly in across the embankment in search of food.

Unlike the uniform mangrove forest outside the embankment, the grassy marshland permanently enclosed inside is a highly complex mix of freshwater and saltwater wetlands, farmland, and ponds. The flow of water into and out of the Keelung and Tanshui Rivers is controlled by sluices. From the north and east, two creeks and an irrigation channel also feed water into the area, creating a diversity of saltwater and freshwater ecologies.

An important part of what makes Kuantu so attractive to waterbirds is its special food chain. Withered leaves falling from the wetland's green plants are broken down by microorganisms in the mud and water into particles of organic material that are consumed by small creatures living in the mud. These "benthic" (bottom-dwelling) organisms then become an excellent food source for fish and birds.

The organic particles in the soil are also washed by the tides into the nearby sea, where they attract hordes of fish, shrimps, mollusks and crabs to feed and breed. These too provide food for the waterbirds.

The Kuantu Nature Reserve has many high powered telescopes and on-site volunteer guides. It is an excellent venue for schools to conduct lessons on ecology.

Vitality in the mud

Because the species living in the marsh near the river mouth have to cope with the adverse conditions of oxygen-poor, highly saline soils, those that are able to survive are highly adaptable, and although the number of species is not great, they reproduce prolifically. This is one reason why among the more than ten recognized types of wetland, "estuarine wetlands" are the most biologically productive.

Taiwan has many estuarine wetlands, but the most representative in terms of size and richness of birdlife are the Tsengwen Estuary and Ssutsao in Tainan, Kuantu in Taipei, and the Lanyang Estuary in Ilan.

Although Kuantu does not boast such rare visitors as the Tsengwen Estuary's black-faced spoonbill, the variety of water and land birds attracted by its diverse habitats, and its easily accessible location on the outskirts of Taipei, have made Kuantu a prime destination for birdwatching in northern Taiwan for many years.

Among these diverse habitats, the open water mainly plays host to waterfowl such as green-winged teal and northern shoveler. They are filter feeders, straining organisms out of the water with a comb-like structure inside their bills. On the mudflats are mainly shorebirds of the sandpiper and plover families. From the mud they peck "polychaete" and "oligochaete" worms (benthic organisms similar to the red wigglers and ragworms sold in sea angling shops). The birds most often seen on grassy marshland are waders of the heron and grebe families, while those on farmland or grassland are mainly resident land birds, especially sparrows and prinias. But in winter when the fields are lying fallow, a few waterbirds appear there too.

The mangrove swamp where the salt and fresh water meet is a harsh environment. Although the variety of species that reproduce here is small, their numbers are abundant. It is a feeding paradise for waterbirds.

Migrants' paradise

On the mudflats beneath the Kandelia mangroves many waterfowl roost, while the trees' canopy not only provides perches for the light-vented bulbul, but is also an important roosting and nesting place for birds of the heron family.

The autumn months of September and October are the peak time for waterbirds to pass through Taiwan on their southward migrations. Fifty to 60 species of shorebirds, waterfowl and waders arrive in Kuantu at this time. After the "transients" among them have left, the "winter residents" that remain are the main focus of winter birdwatching. Although fewer species are present than in autumn, their populations are large. The sight of thousands of green-winged teal on a sandbar is particularly splendid. Indeed, it is the vast numbers of teal that gather here that are responsible for Kuantu being designated an "important bird area." The spring months of April and May are the highpoint of the year for birding in Kuantu: at this time one may easily observe 50 to 60 different species in one session.

In late winter or early spring, to take a breather from hectic city life by looking out from Kuantu Nature Park over this patchwork of grassy marshland, ponds, sand dunes and streams, where reeds and water plants dance in the cold wind that whips up the waves, and seeing the many kinds of waterfowl swimming on the water, a gray heron standing like a lonely warrior at the water's edge, or an occasional bird of prey appearing in the sky, is surely the most poetic of feasts for the soul.

In the face of an oxygen-poor and highly saline environment Kandelia has evolved a way of live propagation without seeds.

Ubiquitous marshes and ponds in the Kuantu Nature Reserve in Taipei create an idyllic scene. In early spring as winter draws to a close, birds flit among the gentle waves, as if right out of a poem or picture.

Ubiquitous marshes and ponds in the Kuantu Nature Reserve in Taipei create an idyllic scene. In early spring as winter draws to a close, birds flit among the gentle waves, as if right out of a poem or picture.