The World Migratory Bird Day (WMBD) was initiated in 2006 and is an awareness-raising campaign highlighting the need for protection of migratory birds and their habitats. In the second weekend each May, people around the world take action and organise public events such as bird festivals, education programmes and bird watching excursions to celebrate the WMBD.
This year, the day will be celebrated on May 11-12 with the theme "Networking for migratory birds". The WMBD is expected to connect the world and bring together organisations, governments and dedicated people to protect migratory birds for future generations. The day works as a network to increase public knowledge about migratory birds and their importance and also connects groups of people to share, celebrate with and learn from each other.
This year’s theme also highlights the need to cooperate and network amongst organisations and people to conserve migratory birds. Since the migration routes often cross many nations and even entire continents and oceans, an effective management strategy requires joint action in the form of international cooperation. Collective conservation actions by nature conservation organisations, scientists, governments and the general public are needed to ensure survival of the migratory birds.
The survival of migratory birds depends on the availability of well-connected habitat networks along their migration routes. This year’s theme aims to emphasise both ecological networks and the networks between organisations and individuals and their mutual importance for long-term conservation of migratory birds.
Suitable habitats are vital for migratory birds as they provide the areas necessary for feeding, resting and breeding. These birds travel huge distances, sometimes comprising thousands of kilometers. However, human activities, directly or indirectly, damage these sites through habitat fragmentation and degradation, thereby posing a threat to the bird species. Many sites that birds depend on are under threat from human activities, posing a grave risk to their species. Direct human activities such as land reclamation and deforestation as well as indirect human influences such as climate change damage these sites through habitat fragmentation and degradation. large numbers of important sites have already been damaged, or lost entirely. Consequently, conservation of the remaining important sites is crucial for protection of the migratory avian species.
In many parts of the world, wetlands are under threat of degradation or disappearance. Vast water body and biodiversity is a major factor for visit of thousands of birds from different regions of the world. Along with this, climate change is emerging as the greatest threat to natural communities in most parts of the world’s ecosystems in coming decades. Bird species are great indicators of climate change. It is affecting birds’ behaviour, distribution and population dynamics and is implicated in a complete breeding failure in some populations. The problems faced by bird populations worldwide, especially by migratory birds that may be travelling up to tens of thousands of miles, mean that drastic changes in any single world region could push a wide variety of the species out of existence.
Migratory birds visit most part of India and are not confined to a few areas. With a view to escaping severe cold in winter and also in search of food, the birds travel from the remote lands like Siberia, Mongolia, Caspian lake, Baikal lake, ladakh and the Himalayas foothills to visit the wetlands in India. In comparison to other Indian wetlands, maximum numbers of migratory birds are seen in the Chilika lagoon in Odisha. The Chilika lake is the largest lagoon in Asia spread over three coastal districts of Puri, Khurda and Ganjam. It is connected to the Bay of Bengal. The water spread area of the lagoon varies between 1,165 sqkm in monsoon and about 906 sqkm in the pre-monsoon period.
Ornithologists feel that early snowfall and scarce food might have led the birds to migrate to the Chilika. Experts this time felt that the abundance of food and favourable weather attracted birds to the Chilika as the lagoon’s location on the coast in the tropical zone spares it from extreme temperatures. The Chilika catchment enjoys a typically tropical climate with an average annual maximum temperature of 39.9°C and a minimum temperature of 14.0°C. It is bounded by hills and hillocks. The Chilika is recognised as one of the most important wetlands in the world because it is home to a phenomenal variety of birds. It has always been potentially able to provide excellent hospitality to the birds with favourable weather, food and shelter. There are many island sanctuaries in the Chilika with the island of Nalabana as a major attraction. Nalabana is a lowlying marshy island of about 35 km2, covered with low vegetation. Designated as a bird sanctuary, it forms the core of all tourist attractions in the Chilka region due to the presence of variegated flora and fauna.
The lagoon hosts over 160 species of birds in the peak migration season, the winter. The birds travel possibly up to 12,000 km to reach the lake. The lagoon is at present facing the problems of an overall loss of biodiversity.
The ecological character of the lake is influenced by hydrological regimes and is vulnerable to changes due to anthropogenic as well as natural factors. The lake has gone through tremendous ecological changes since last decade. It had been facing problems like siltation, shrinkage of area and choking of the inlet channel, which led to decrease in the salinity gradient, proliferation of freshwater weeds, followed by a decrease in fish productivity and an overall loss of biodiversity.
The growth of chemicals-based industries in the catchment areas, agriculural intensification in the Chilika basin and the spread of prawn-culture ponds have increased pollution and eutrophication of the lake. The presence of toxic-heavy metals including mercury, lead, copper, chromium and nickel in the lake has been reported. In addition to its impact on fishing, the growth of weeds has contributed to drastic reductions in the bird populations, particularly noted near Nalabana. Deforestation in the Chilika basin and hunting are also contributing to this decline.
Due to the degradation of wetland habitats, the populations of various bird species are dwindling in the Chilika. In 2010 and 2011, the number of birds visiting the lake were 9, 24,578 and 8,83,072, respectively. In 2012, birds numbering 8,77,322 flocked to the lake which is less by 5,750 compared to the previous year, as per the latest bird census. This may be due to the rise in temperature. Another reason may be that the depth of the lake has decreased. If this trend continues, the numbers of birds will reduce in the coming years. This decline, in turn, has resulted in a substantial decrease in international tourists and ecotourism, which used to contribute greatly to the local economy.
In the Chilika, bird conservation requires a continuous adaptation based on the review of changes in various components of ecological character of the wetland. There is a need for ecosystem conservation and sustainable resource development and livelihood improvement supported by institutional development, communication, education and public awareness. Ecosystem conservation would comprise catchment conservation, water management and biodiversity conservation. Siltation is the major problem of the lake. There is a need to reduce this load by suitable plantation and watershed development programme in the catchment areas.
The State Wildlife Organisation in collaboration with the Chilika Development Authority (CDA) has taken several steps for protection and conservation of the local and migratory birds. Besides, awareness and cooperation of the local people are highly essential. Public awareness and concern are crucial components of migratory bird conservation. Citizens who are enthusiastic about birds, informed about threats and empowered to become involved in addressing those threats, can make tremendous contributions for migratory bird conservation of the Chilika lake.
(Dr Mayarani Praharaj works at the Department of Architecture, College of Engineering and Technology, Bhubaneswar)