202002/27
Spring is right around the corner, and the breeding season of the African sacred ibis is fast approaching. The Forestry Bureau under the Council of Agriculture announced that it would undergo active removal of the African sacred ibis, an invasive bird species, in 2018. The Bureau brings together all the county and city governments where the African sacred ibis is distributed to carry out joint strikes. The comprehensive removal of the bird uses two methods: reproductive control and adult bird removal. The plan is to suppress the expansion of the ibis population in the short term, and clear the population over the years to prevent its continuous expansion and the harm it does to the native animals and the ecosystem. In this regard, the Council of Agriculture and the Executive Yuan gave their full support and hope to speed up the process.
African sacred ibis are originally from Africa and the Middle East. It was introduced to a private zoo for the first time in Taiwan forty years ago, but later, it accidentally escaped into the wild. Since 1984, there have been records of field sightings in Guandu and other places in Taipei. Due to the birds' excellent adaptability and lack of natural predators, its population has increased year after year. At present, it has widely spread to the coastal wetlands of the counties and cities of eastern Taiwan, and has further encroached upon inland low-altitude mountain areas. Currently, only Hualien and Taitung counties have escaped its invasion. The Forestry Bureau estimated that there are roughly 3,000 nests and 8,000 birds in the total population of Taiwan from counting the nest numbers in the nesting areas over the past two years.
According to the Forestry Bureau, this large white bird with a black curved beak has a habitat and feeding habits that overlap with the native heron species, and it has begun to compete for survival resources with the native herons and may also be harmful to the species it feeds on. When the birds gather in large numbers for nesting, they remove the top branches and leaves, thereby destroying the vegetation cover, and they can even cause agricultural losses due to their foraging behavior in the farm fields. The removal of the species is urgently required, and long-term removal of the eggs, fledglings, and adult birds must be carried out continuously for the suppression of such a large number of African sacred ibis to work.
The Forestry Bureau pointed out that it has been monitoring the distribution and ecological habits of the African sacred ibis in Taiwan for a long time. After confirming that the ibis has become a risk to the local ecosystem due to the rapid increase of population groups, the decision for its active removal was made in 2018. Studies are also being carried out to improve the various removal methods tailored to local conditions. Since 2019, after gaining full knowledge of its habits, breeding nests, as well as analyzing the effectiveness of various removal methods, the two strategies of reproductive control and removal of adult birds were clearly set out. Professional companies have been commissioned to carry out reproductive control and to remove all eggs and fledglings found in the nesting areas, and set up traps and nets to capture the adult birds in the nesting areas. Furthermore, through negotiation with police units and in compliance with firearm control regulations, the removal method by shooting (commonly used abroad) has been employed though the use of legal weapons, including crossbow, fishing harpoon, hunting bow, and air gun. Indigenous hunters have been requested to use their legally self-made shotguns to improve removal efficiency.
Forestry Bureau statistics on the removal results in 2019 show that a total of 5,831 eggs and 1,210 fledglings were removed from the main nesting areas in Guandu, Taipei; Wugu, New Taipei; Kouhu, Yunlin; Fangyuan, Changhua; Dongshi, Chiayi; Budai, Chiayi; and Linbian, Pingtung. A total of 825 adult birds and 398 subadult birds that appeared near the nesting areas were removed. Out of these results, the commissioned indigenous hunters managed to remove 812 adult birds in the second half of the year, showing that shooting is indeed a very efficient removal method.
African sacred ibis is the original form of Thoth, the Egyptian god of wisdom. The bird is extremely intelligent, has high visual acuity, and is very alert. Adult birds will flee and hide when nets are cast or a gun is fired. In addition, they often choose concealed and inaccessible nesting areas, so once the invasion reaches a stable population, it is very difficult to remove. Based on France's experience of African sacred ibis removal from the country's western regions, more than 1,700 nests and an estimated 5,000 African sacred ibis were observed in 2006; from 2007, the two removal methods of shooting and destroying eggs were used; and by 2013, after a full 7 years, the wild population was reduced to 280 or 300 nests.
After obtaining initial results in 2019, the Forestry Bureau will increase its removal capacity this year, further include local governments and conservation groups, and use local advantages to monitor the nesting areas and track population groups of the African sacred ibis. It is hoped that no group overnight resting locations and nesting areas will be missed, and all eggs and fledglings can be removed as soon as nesting areas are found. The forest district offices under the Forestry Bureau have also set up removal teams composed of forest rangers. In cooperation with the indigenous hunter removal teams that have already been formed in northern, central, and southern Taiwan, they continue to search and track the various locations where African sacred ibis have been found and apply their sharpshooting skills to remove the adult birds.
Now that the season has entered early spring, it is already possible to observe African sacred ibis actively searching for food in the spring paddy fields around the country, and individuals have begun to gather together. It is estimated that this year's breeding season will soon begin. The Forestry Bureau urges the public to immediately report online any sightings of the African sacred ibis or any possible nesting sites on the "Prevention and Control of Invasive Sacred African Ibis" Facebook page. The information will allow the Forestry Bureau and the counties and cities to effectively determine the real-time distribution of the African sacred ibis for more accurate removal.