Saturday, October 12, 2013

Bird Festive Season

Season means many different things to many people. Some prefer monsoon for their crops to grow, while others look for summer for their business to flourish. And there are people waiting for a new season to welcome visiting birds. In fact, the avian visitors remind people of beginning of a new season.


The migratory birds’ spectacular flight reminds farmers to plant new crops in their field. Thus the saying in Nepali: "Karyang kurung aayo, kakro pharsi ropa" or, Here come cranes, plant cucumber and pumpkin in your nursery-lane.

When Hem Subedi, a birder and conservationist, sees numerous White Wagtails flitting around, they inform him of arrival of Dashain festival–the biggest festival of the Hindus, in October– and turning weather into colder each day afterwards. He is expecting this winter to observe Ruff, Northern Lapwing, Falcated Duck and Eurasian Curlew, that are irregular winter visitors for Chitwan. Tek Bahadur Gurung, a nature guide and member of Bird Education Society (BES), is really excited to see new visiting birds every now and then during migratory season. He loves to share the finding among friends. "It's like a festival for us", says Tek.

With touch of coldness on the air, birds start to arrive in Chitwan to spend their winter holidays. Chitwan, a well known bird hotspot with more than 600 species, attracts a huge number of migratory birds seasonally. According to recent data of BES, some 147 species have been recorded as winter visitors and some 61 species are summer visitors for Chitwan. The winter birds descend down to warmer plains in the south from much colder areas in the north to avoid the harsh weather condition and shortage of food; whereas the summer birds travel towards north from south especially for breeding purpose.

Birds go for sojourn to the places where there is plenty of food with less competition for resources; where they feel secure, and they have perfect environment for resting, breeding and raising their offspring. Chitwan, with all its abundant resources, provides perfect environment for birds that visit during summer and winter.

Nepal's climate is governed by the monsoon, a seasonal wind that draws moisture up from the Indian Ocean from approximately mid-June till early October.  It brings heavy rain and snow everywhere except to the north of the main Himalayan Chain. In general five seasons prevail in Nepal: autumn, winter, spring, pre-monsoon and monsoon. The winter is mostly dry and cold from December to mid-February and the summer period, covers partly spring and partly pre-monsoon, is generally dry and hot from March to June.   

Wintering birds begin to arrive in Chitwan from early September and this trend is somewhat similar all over the plains of the country. They come throughout mid-Winter and stay until February before they make journey back home. White Wagtail, Greenish Warbler, Blyth's Reed Warbler, Common Greenshank, Green Sandpiper and Common Sandpiper are among the birds that arrive early. Many different species of ducks and water birds arrive in large number during October - November.

Wintering birds start their journey from their breeding grounds in the north – mainly Tibet, China, Cambodia, Laos and Siberia. While travelling though high Himalayas, they follow the gorge; and most of them which visit Chitwan come through Kali Gandaki Gorge that lies north-west from the Chitwan Valley.

Members of BES, once recorded birds travelling from Lake Baikal, Siberia. Hem confirmed, "Some 10 years ago, we saw a Black Stork with a ring on the leg that led to investigation to find out the birds coming from Lake Baikal."

Whole lots of birds migrate during winter but only few of them spend time in Nepal. In fact, majority of them directly fly towards south, parts of India and Sri Lanka. Many raptors do not come to Chitwan but go to west through Mahabharat mountain range. Most of the cranes, stilts, ducks and plovers directly make their journey towards south.

Those birds, which head towards far south, begin their journey earlier than others. Most of them do not make much stopover on the route. On their return journey, however, they make stopover at various places in Nepal during March-April. They gather enough fat before they cross the high Himalaya. Tika Giri, bird expert, elaborates that many flocks of Bar-headed Goose can be seen in Koshi, an important site especially for waterbirds in far eastern Nepal, during March-April. "They are, in fact, coming from south to go north" he said.

White Wagtail, Blyth's Reed Warbler, Greenish Warbler, Chestnut-crowned Bush Warbler and Ibisbill are among the birds that descend down to plain from Mahabharat during winter. Tika emphasized, "These are winter visitors but could not be referred as migratory birds. Migratory birds are those coming from other countries."

March-April is regarded as the best period for bird watching when you can see many wintering birds that are augmented by summer visitors. Chitwan's climate in summer, when the day is longer and temperature is optimum, is perfect for birds to come for breeding and raising offspring. They mainly come from southern regions -India, Sri Lanka, Indonesia, Thailand, Malaysia and Cambodia. Few birds such as Hooded Pitta, Lesser Cuckoo and Crow-billed Drongo also come from as far as Africa. From June, these birds start to return back with their offspring, except cuckoos. As their juveniles are raised by other birds, cuckoos have luxury to depart early after laying eggs on other's nest. Young cuckoos themselves travel back home following their innate sense.

Study and observation of wintering birds is going on as local bird watchers, nature guides and members of BES are doing Mid-Winter Water bird Census in and around Chitwan National Park annually in coordination of Bird Conservation Nepal and International Waterbird Census. Recent observations indicate that species diversity is good but population is decreasing. Certain sites, where human disturbance is less, have more birds than others which are more disturbed. Long stretch of Rapti and Narayani River, that forms the southern boundary of Chitwan National Park, is still good habitat of both resident and migratory birds. Some of the important wetlands such as Devi Tal, Lami Tal and Tamor Tal inside the Park, and Bis Hazari Tal inside Barandabhar Forest Corridor, which used to be favorable lakes for migratory birds, are fast deteriorating by the invasion of alien plants.
 
The human induced threats to migratory birds are more than ever that attribute to the decline of bird population. Hunting and associated human disturbance have been reported in areas where birds take temporary refuge during their journey. Global warming and climate change have their impanct on their great journey but habitat loss and degradation are the major threats for migratory birds. Reduced food availability due to over-fishing, poisoning, increased use of pesticides and the spread of invasive plants in wetland areas has contributed immensely for the decline of bird population.
 
Birds are known as greatest travelers of all the travelling beings. Indeed, they complete thousands of miles of journey. During the journey, they apparently get tired and run out of energy. They need rest and food to revive energy to continue the journey. So it is essential to protect both habitats where they take refuge and where they spend whole winter or summer.

We have culture of respecting guests as gods, "Atithi deva vawa". Birds are also our guests. It is our responsibility to protect them so that they continue to make their great journey unhindered, around the world.

No comments:

Post a Comment