Conservation through Eco-Friendly Farming:

In a water caltrop field in the rural Guantian District of Tainan City, a pheasant-tailed jacana (Hydrophasianus chirurgus), known in Chinese as the “water caltrop bird,” is stretching out its long legs and waving its long, slender tailfeathers. In the manner of a martial artist flitting across rooftops, it strolls atop the floating leaves of the water caltrop plant while feasting on apple snails and aquatic insects.

According to surveys by the Jacana Ecological Education Park in Guantian, the number of pheasant-tailed jacanas in the district has risen from less than 50 in 1998 to more than 2,000 for three consecutive years, from 2021 to 2023. In the winter of 2024 the total population of these birds in Guantian reached a new historic peak of more than 3,000 individuals.

Instead of discarding water caltrop hulls, one can dry them in the sun, then boil them in water with jujube and longan to make water caltrop tea.

Opportunity out of tragedy

Following widespread destruction of its habitat through land development, in 1989 the pheasant-tailed jacana was listed by the Ministry of Agriculture (MOA) as a Category II protected species (“rare and valuable”).

However, in 2009 there was a mass die-off of the jacanas, with 85 of the birds expiring in rice paddies. The reason turned out to be that they were poisoned by eating rice grains that had been mixed with pesticides. Farmers were sowing seed rice directly into the soil instead of planting out seedlings, and they mixed in pesticide to prevent birds from eating the seeds.

Despite the promotion of organic farming as a solution, it was virtually impossible for water caltrop farmers to prevent their fields in Guantian, with their narrow dividing ridges, from being contaminated by pollutants from adjacent farmland. This made it difficult for these fields to be certified as organic.

In order to protect the pheasant-tailed jacana, the Forestry and Nature Conservation Agency of the MOA commissioned the Tse-Xin Organic Agriculture Foundation (TOAF) to find a “middle way” to solve the problem. They came up with the idea of promoting the “Green Conservation” certification mark to encourage farmers to not use pesticides or chemical fertilizers in the cultivation process and thereby keep their water caltrop fields free of toxins.

The breeding season of the pheasant-tailed jacana normally runs from April to October, which happens to overlap with the harvest season for water caltrops.

Green Conservation

Wang Yao-wen, who previously did construction formwork and only returned to his hometown to start farming at age 30, first raised tilapia in his water caltrop fields. He never expected that right after he sprayed pesticide to protect the water caltrop plants, the fish would all go belly up and die. When the TOAF held its first explanatory meeting about eco-friendly farming in 2010, Wang decided on the spot to switch over to this type of agriculture and join the ranks of those protecting the pheasant-tailed jacana.

Wang, now a veteran user of the Green Conservation mark, has persevered in eco-friendly farming for the last 15 years. He says that by not spraying pesticides he also avoids exposing himself to toxins. When some friends wanted to use water caltrop hulls, which contain organic germanium compounds, as a means to enhance the functioning of organic pesticides, they sought out toxin-free water caltrops but were unable to find any.  “Later they came to me, so I sold some to these people who had gone to so much trouble to find them.” He had never expected that growing water caltrops would also turn out to be doing a good deed.

Chen Jinyu has persevered in using eco-friendly farming methods, and her harvests have steadily increased year by year.

Eco-friendly vs. conventional agriculture

Of the water caltrop farmers practicing eco-friendly agriculture in Guantian, Huang Wenchuan has the highest production volume. Huang’s father was the first farmer to introduce the water caltrop variety Trapa natans var. quadrispinosa from China into Taiwan. Because of its rarity, there was competition to purchase the first year’s crop, some of which was snapped up by middlemen at the wholesale market price of NT$30 per Taiwanese catty (600 grams) and sold on for NT$40 per catty.

Huang’s wife Chen Jinyu began cultivating water caltrops using eco-friendly farming nine years ago, with the harvest steadily increasing over time. When Huang Wenchuan retired from the post office four years ago, he began farming with the mindset of an academic. In 2023, the water caltrop harvest on each fen of land—about 970 square meters—exceeded 2,000 kilo­grams, which brought the yield up to the same level as conventional farming.

In Guantian most water caltrop farmers rotate their crop with paddy rice. After the water caltrop harvest in late fall and early winter, farmers plant paddy rice in December. Rather than using the traditional method of broadcast sowing seed rice, Huang insists on transplanting rice seedlings by machine in neat furrows, and when weeds emerge he floods the fields to drown them. The rice plants are widely separated, giving them adequate ventilation, and they suffer little damage from pests and diseases.

Wang, now a veteran user of the Green Conservation mark, has persevered in eco-friendly farming for the last 15 years. He says that he himself avoids exposure to toxins by not spraying pesticides. When friends wanted to use water caltrop hulls, which contain organic germanium compounds, as a means to enhance the functioning of Chinese herbal medicines, they sought out pesticide-free water caltrops but were unable to find any. “Later they came to me, so I sold some to these people who had gone to so much trouble to find them.” He had never expected that growing water caltrops would also turn out to be doing a good deed.

Black-winged stilts.

A pheasant-tailed jacana (right)and a common moorhen (left).

An egret.

Aesop’s Fable for the jacana

The jacana’s breeding season normally runs from April to October. Water caltrop farmers cultivate two varieties of their crop, Trapa natans var. bispinosa and Trapa natans var. quadrispinosa, which have different growing seasons, providing the birds with a suitable foraging and breeding habitat for longer periods.

To encourage farmers to manage jacana habitats, the Tainan City Government and agricultural agencies offer subsidies for measures such as creating habitat spaces and protecting nests. For example, in 2011 there was a payment of NT$4,000 for protecting a nest with one to two chicks, and NT$8,000 for a nest with three to four chicks, as an incentive for farmers to safeguard the nests of pheasant-tailed jacanas in their fields.

At first Wang Yao-wen’s wife didn’t know that the nests in their fields belonged to jacanas, thinking instead that the eggs were laid by common moorhens, and she collected them to make hardboiled eggs. Wang recognized these shiny bronze-colored eggs as pheasant-tailed jacana eggs, and he told her: “If one egg hatches out and produces a chick, we can get a payment of NT$4,000, so if five eggs hatch we would get NT$20,000. Why did you bring them home?” It really was a case of a jacana version of Aesop’s Fable “The Goose that Laid the Golden Eggs.”

Now that the jacana population has been restored to relatively high levels, the incentive payments have been reduced. However, farmers are already accustomed to treating the jacanas as “long-term residents.”

The pheasant-tailed jacana is polyandrous (multiple male partners for each female), with the males responsible for incubating the eggs. After a female jacana lays a clutch of eggs, she searches for a new partner nearby and builds another nest. This is a very rare reproductive model among bird species. Wang says that the fathers who look after the nests are very sensitive to potential threats. For example, if a stray dog or a snake happens by, they will feel unsafe, and overnight they will kick over the nest and rapidly relocate the eggs to a spot at least ten feet away.

Lin Binghuo applies habitat management concepts to his water caltrop farming practices, turning his fields into a paradise for wildlife.

Habitat creation, ecological paradise

TOAF staffer Pansy Sun notes that by increasing the amount of land cultivated with water caltrops, the habitat of the pheasant-tailed jacana can be expanded.

Caltrop farmer Lin Binghuo plants his water caltrops with habitat creation in mind. He has established an ecological pond, using 20% of his fields to create a bio­diverse environment.

Lin relates: “My main income comes from pickling watermelons. I held on for eight years with a never-say-die mentality until I finally began to earn a profit from my eco-friendly fields. The most important thing is to get support from sales channels. With help from the ‘Hawk Princess,’ Lin Hui-shan, Guantian water caltrops with the Green Conservation mark began to be sold in PX Mart outlets under our own brand name and we started earning money, enabling us to devote more attention to animals.”

Lin has set up wildlife cameras in six areas to observe animal behavior. For example, the papaya trees that grow on the embankments between his fields provide light-vented bulbuls with their favorite food, while in return the bulbuls eat his leaf beetles.

Leaf beetles are water caltrop farmers’ most worrisome pest. The beetles eat the verdant green leaves of the water caltrop plants, leaving them looking like they have been burned to a crisp, similar to skin that has been infected with anthrax. After an infestation, harvests fall by at least half.

In the fields, turtles and small rodents love to eat water caltrops, so what can be done? Lin Binghuo tells us he plants water spinach for the turtles to feed on. He adds: “Rodents help me out by eating apple snails, which is something to feel happy about. Moreover, the chain of life has its own balance, and the rodents have many predators, including black-winged kites and crested serpent-eagles in the air and king rat snakes and Oriental rat snakes in the water. As a result, only the most nimble and elusive rodents survive in the fields.”

Conservation-minded farmers cultivate their fields in such a way that they also provide excellent habitats for rare and precious wildlife, contributing to the goal of restoring animal populations. From left: Wang Yao-wen, Zheng Yinghua, Chen Jinyu, Huang Wenchuan, and Lin Binghuo.

Eco-friendly farming has transformed water caltrop fields into a safe habitat for pheasant-tailed jacanas. (photo by Chen Fushun)

Sustainable cultivation

According to TOAF, from 2011 to 2024 a total of 648 farmers across Taiwan have applied to use the Green Conservation certification mark, covering 916 hectares of farmland. Already 46 species of rare and valuable animals are receiving protection, and 412 farming households are involved in habitat ­management.

Eco-friendly farming is not only about rescuing the pheasant-tailed jacana, as endangered species such as the leopard cat and the eastern grass-owl also benefit from conservation activities and government policies. As TOAF CEO Su Muh-rong has remarked, eco-friendly farming can be considered as a component of organic agriculture, broadly understood, and is likewise beneficial for soil health, ecological balance, and mitigating the effects of global warming. Green conservation measures promote farmland biodiversity and there are tremendous benefits from building agricultural ecosystems.

Pheasant-tailed jacanas build their nests, mate, lay eggs, and brood in water caltrop fields, so they are also known as “water caltrop birds” in Chinese. (photo by Chen Fushun)