Saving Silence 04: Migratory Birds' Songs at Yong'an Qieding Wetland Threatened by Highway Noise
Text / Lin Kunhai (Secretary-General of the Kaohsiung Wild Bird Society) Photography / Tu Jianfeng
Compared with winter, the wetland looks somewhat empty in midsummer. Most migratory birds had already returned north in March-April, preparing to breed in the north. At this time, Taiwan's wetlands enter what birders call the "fifth and sixth months barren, seventh and eighth months scattered" bird-drought season. Even so, the coastal wetlands are still full of vitality. Resident birds everywhere are also working hard to survive and breed the next generation: Kentish plovers, black-winged stilts, common moorhens, little grebes, plain prinias, and reclusive wren-warblers are regular visitors to the wetlands, singing as always, defending territories, calling to their young, and driving away enemies. Although they are not as spectacular as the hundreds or thousands of migratory birds in flocks, the wetlands are still full of life!
With a "chirp" from a kingfisher, its water-blue back streaks across the water's surface, as if leaving an exclamation mark of nature! When observing birds in the field, besides using your eyes, more often you use your "ears"!
Forest birds often hide among dense leaves and branches, making their forms hard to see clearly; by contrast, bird calls are a better identification tool. Birds inhabiting woodlands convey messages through calls. Whether courtship sounds, alarm or defensive sounds, or repeated calls to their young, they can always travel clearly and far through dense forests. In bird surveys or birdwatching competitions, bird sounds can become official records; they can even be the main basis for bird surveys!
The Importance of Wetlands
In July and August, Kaohsiung had a long stretch of rain. On 719, more than 100 mm of rain fell within just 12 hours. Many places were severely flooded, causing traffic inconvenience and losses to people's property. Such disasters also show that under extreme climate, high-intensity rainfall has become the norm. In addition to strengthening drainage measures, improving tolerance and response capacity for flooding is also an important consideration. At this time, the preservation of wetlands, river floodplains, and permeable green space in cities becomes even more critical and important!
The Kaohsiung City Government's proudly promoted wetland corridor policy covers 21 wetlands, including the national-level Zhouzai Wetland, the large-area Yong'an Salt Pan Wetland, and artificial detention ponds hidden in dense residential areas. From natural to artificial, from large areas to small detention ponds, for both people and wildlife, wetlands are not only places to live, but also the best places to avoid danger and flood disasters, get away from heavy traffic, and get close to nature.
From Salt Pans to Wetlands
It is less than a 50-minute drive from downtown Kaohsiung to Yong'an Wetland. The scenery changes from densely populated high-rise buildings to an endless scene of fish ponds in the blink of an eye. Yong'an District is a professional fish-farming area. The main farmed fish are grouper and milkfish. The grouper farming area is about more than 300 hectares, with an annual output of more than 8,000 metric tons. Both quality and quantity are second to none across Taiwan, and it is known as the hometown of grouper. This is also the only remaining salt pan relic in all of Kaohsiung: the Kaohsiung Wushulin Salt Field. A splendid historical building in Baroque style, the "Wushulin Salt Manufacturing Corporation," stands in the middle of the salt pan, guarding a century of salt-field history.
Yong'an Wetland was formerly called "Wushulin Salt Field" and is part of Kaohsiung's salt pans. To the north, across Xingda Harbor, is the "Zhuhu Salt Field." Because of the construction of Xingda Deep-Sea Fishing Harbor, it was covered by sand extraction and no longer looks as it once did! The former "Zhuhu Salt Field" is now called "Qieding Wetland," and it is also one of the stops we are about to visit.
In ROC year 73, Taiwan Power Company purchased Yong'an Salt Field in preparation for use as a disposal site for power plant bottom ash. Due to residents' protests, it could not be used for a long time and has remained idle until now, thus becoming a place for many migratory birds to migrate and overwinter as they travel south and north. It was also designated by BirdLife International as an Important Bird Area (IBA TW 041). In ROC year 96, it was recommended and assessed as a locally level national important wetland. On February 2, ROC year 105, the Wetland Act was promulgated and implemented. In ROC year 107, it was announced as a locally level national important wetland, and its area was reduced from 130 hectares to 41.25 hectares. The salt flats to the north serve as the plant area for the gas unit renewal of Xingda Power Plant.
In summer, the water level at Yong'an Wetland is slightly higher, and winter migratory birds are long gone. On the water surface, you can see little grebes bobbing up and down, and in the distance, medium-to-large wading birds such as little egrets and black-winged stilts. The little grebe is one of the very few local resident waterbirds that dives to catch fish. Its fishing method differs from that of the kingfisher, which plunges into the water from above; the little grebe's legs are positioned toward the rear of its body and are webbed, making it good at diving but poor at walking on land, so it spends almost its entire life with water! In recent years, it has benefited from the rising water level in the wetland! On the contrary, other short-legged waterbirds such as the Oriental plover, Kentish plover, and red-necked stint in the sandpiper and plover family have also declined greatly in number. In addition to the increase in rainy days and rainfall, human control is also one of the reasons.
