Kathmandu– A growing number bird species are facing threat of extinction due to the impact of climate change on their habitat and food. The birds that were abundantly seen only 30 years ago have not become rare. Ornithologist Dr Hem Sagar Baral say the birds have become extinct due to climate change.
Dr Baral said around two dozen Red wattled lapwing (Titahari) birds were seen in the Rapti River area, south of Hetauda, during the winter of 1990. In the 90s, the birds were widely found in the Trishuli, Rati, Gandaki, Budhi-Gandaki, and Bhote-Koshi, among other rivers. “The birds found in flocks then can’t be seen anymore,” said Baral. He said the Red wattled lapwing is just an example of endangered species of bird. The number of other birds found in abundance until 30-40 years ago has sharply decreased. The populations of birds such as Indian cuckoo, goose and black-bellied tern are declining gradually.
In 1996, around a dozen nests of black-bellied tern was found in the area—eight kilometers south of Narayani River. But the birds cannot be seen in that area.
Only until the winter of 1986, the area around Koshi Barrage was covered with goose. Once the number of goose that arrive from Tibet and Siberia to Koshi Tappu area were recorded at 50,000. But now it is hard to find 10,000 birds even after visiting the entire Koshi Tappu area. According to a study done in 2016, 168 species of birds have been put on the endangered list. Nepal Birds Conservation Association Chairperson Rajendra Gurung said the rate of extinction of birds is growing.
Impact of climate change
According to bird experts, the major cause for the decline in the number of birds is the impact of climate change on their habitat and food. The Titahari birds found along the banks of Kyanjing in Langtang River, Rasuwa, Tukuchhe of Kaligandaki River, Pangboche of Solukhumbhu, Beding region of Gaurishankar are facing the crisis of habitat because of the sudden melting of ice. The rise in water level due to ice melting has affected their habitat.
“Titahari builds its nest based on the past pattern of rise and fall of water level in the rivers. But the pattern has changed in recent times,” said Dr Baral. He said the number of Titahari has been dropping as a result of abrupt melting of ice due to rise in temperature.
Recent studies show that the glaciers and glacial lakes are melting fast due to rise in temperature.
According to the Department of Hydrology and Meteorology, the temperature is increasing at a rate of 0.08 degree Celsius. Similarly, the average annual maximum temperature of Nepal has risen by 0.056 degree Celsius. In the past 30 years, Nepal’s temperature has risen by 1.6 degree Celsius thereby increasing the number and size of glacial lakes.
Head of geography department at Tribhuvan University, Dr Narendra Khanal said the number of glacial lakes have increased to 2,168 until 2010 in Koshi River basin, while there were only 1160 glaciers until 1977. The area covered by glaciers has increased to 127.68 square KM until 2010 from 94.44 square KM in 1977. The glaciers are increasing at the similar rate in Tibetan region.
Nepal Bird Conservation Association Chairman Gurung said two kinds of birds are found in Nepal—native and migratory. The number of migratory birds that come to Nepal from Tibet and Siberia to escape winter has been dwindling. Dr Baral said the numbers of migratory birds dropped as the temperature of their native place became warm enough due to climate change.
Insects and worms are the main food of birds and they are seen mostly during the flowering season of plants. However, the time for flowering has also changed due to climate change. Dr Baral said the numbers of birds such as cuckoo, black-bellied tern, dongo (Chibe Chara) and Theuwa have dropped due to lack of enough food during the hatching of chicks. On the other hand, the birds of Terai have started appearing in the hills, and the birds from hills are spotted in the mountain region.
According to a study done by bird conservation association, (Red-beaked) Lal-Chuche Theuwa bird was spotted in Kathmandu two week agao, while the (Blue-tail) Nil-Pucchre Murali found in Terai region earlier has made Kathmandu its new habitat. These birds were spotted in groups in Godavari, the association said.
Missing data
No detailed studies have been carried out so far about the impact of climate change on the habitat of birds. Baral says it is not possible to say anything about the growth or decline in population of birds in Nepal as the country started recording the data on birds only 30 to 35 years ago. Though some foreigners did some studies on birds in Nepal, we don’t have any records about that. In 1770, WJ Kirk started counting birds in Nepal for the first time.
Similarly, from Brian Hudson studied birds in Nepal from 1820 to 1846 and discovered 600 species. And other foreign ornithologists also did studies of birds in Nepal.
Dr Baral said the studies on the food status and habitat have shed light on the fact that the number of birds have dropped sharply. He underscored the need for further studies on the same.
Studies conducted in other countries have shown that birds have been affected by climate change. According to Nature Canada, the behavior, heredity, migration and time of hatching chicks have changed due to climate change. A study done in South America showed the birds in the past ten years have started laying eggs six days in advance. Similarly, common murre has started hatching their eggs 24 days earlier in comparison to the past 10 years.
In the same manner, Nature care found that birds started building nest six days ahead even after a minor increase in temperature. The 63-year study also showed that of the 97 birds, 27 birds changed the date of their migration. These examples can also be found in Nepal.
