Posts Tagged 'Migratory Birds'

Bird Migration

An article by Mohan Pai

 
 

BIRD MIGRATION

Mystery of Nature



The Arctic tern flies a phenomenal round trip of 34,000 km per year from the Arctic to the Antarctic and back !

 
The longest known migratory journey is performed twice a year by the Arctic tern (Sterna paradisaea) which from the Arctic winter travels south, right across the world to the Antarctic summer and back again – a distance of over 17,000 km each way.

Arctic tern

 

What is bird migration ?
 
Bird migration refers to the regular seasonal journeys undertaken by many species of birds. Bird movements include those made in response to changes in food availability, habitat or weather. These however are usually irregular or in only one direction and are termed variously as nomadism, invasions, dispersal or irruptions. Migration is marked by its annual seasonality. In contrast, birds that are non-migratory are said to be resident or sedentary.
 

Indian Migratory Birds
 
Indian subcontinent plays host to a number of migratory birds in summers as well as winters. It is estimated that over hundred species of migratory birds fly to India, either in search of feeding grounds or to escape the severe winter of their native habitat. This is because winds usually prevail at higher altitudes and at the same time, the cold temperature at these altitudes helps them in diffusing the body heat, which is generated by their flight muscles. The timing of the migration is usually a mixture of internal and external stimulus.
Migrating birds start on a journey when they feel that they have put on enough fat to provide them energy throughout the journey. Then, the tendency to aggregate into flocks is another determinant of the time of migration. Even after the flock, which has to fly together, has gathered, the birds keep on feeding till the weather conditions become favorable. Thus, apart from the internal clock of the birds and their flock, it is also the availability of food and the weather conditions that play a role in the determination of the time of migration.
 

Why birds migrate?
 
Food, water, protective cover, and a sheltered place to nest and breed are basic to a bird’s survival. But the changing seasons can transform a comfortable environment into an unlivable one — the food and water supply can dwindle or disappear, plant cover can vanish, and competition with other animals can increaseMost wild animals face the problem of occupying a habitat that is suitable for only a portion of the year. Fortunately, however, nature has provided methods for coping with the situation. One method, known as hibernation, involves entering a dormant state during the winter season. The other method, known as migration, involves escaping the area entirely. Because of the powers of flight, most birds adapt to seasonal changes in the environment by migrating. How they do it ? Some birds make the long journey in easy stages, stopping to rest on the way. Others fly great distances without pausing to rest and feed. Some fly by day, some both by day and by night, but most of them speed on their way through darkness after the sun has set. Birds usually travel in flocks. The V-shaped formation of cranes and geese attracts much attention as the bird’s speed across the sky. Swallows, flycatchers, warblers, shore birds and water-birds being to gather in flocks- each with its own kind-and, after a great deal of excited fluttering, twittering and calling, they rise up into the air and away they go. Usually the male birds go first to their breeding grounds in bachelor parties and the female birds follow them in a few days!
Griffon Vulture
 
The movement of birds with the changing seasons was known from the earliest times, but people had strange ideas as to why the birds traveled, or where they went. To explain their absence from a place in a particular season, they said that the birds buried themselves in the mud and slept there throughout the winter! Later, detailed studies of migration started. Information was gained by directly observing the habits of birds, and also by ringing. Bird movements are also studied by creating artificial conditions and studying their effects on birds. Today, most of the information on migration has come from ringing young and adult birds. Ringing is done by capturing a bird and putting on to its leg a light band of metal or plastic. The band bears a number, date, identification mark, and the address to which the finder is requested to return the ring. The bird is then set free. The place where such a bird is shot captured or found dead gives clue to the direction and locality to which the bird has migrated.


Bird Sanctuaries in India

 
Among the most famous bird sanctuaries in India are, the Keoladeo Ghana National Park in Bharatpur, the Corbett National Park and the Sariska Wildlife Sanctuary, part of Project Tiger. These sanctuaries offer wide variety of bird species.
 
Keoladeo Ghana National Park is one of India’s pioneer wildlife conservation centers. Considered to be the best sites for bird watching in the world, the sanctuary annually hosts thousands of visitors who come to view the spectacular wildlife Spread over an area of 30 square km of marshy swamp, kadam forests, woodland and shallow lakes, the sanctuary offers habitat to both nesting indigenous birds as well as migratory water birds. An amazing number of more than 330 species of birds have been spotted and identified in the sanctuary. The Siberian Crane, the finest and rarest of migratory birds, are the cynosure this sanctuary and are regular visitors.Siberian Crane is believed to have existed in this world for over one million years. However it is of great concern that only 125 pairs of these pure white, crimson-billed cranes estimated to survive worldwide. Profusion of marine vegetation, frogs, fish, insects and mollusks, as well fine setting for migratory birds go a long way to make Keoladeo Ghana National Park an ideal place for pelicans, storks, herons, egrets and kingfishers. Breeding females stay in peaceful co-existence and it is of no surprise that one tree can have nests of different birds. The sanctuary is know to have been the best breeding ground for more than a thousand species of birds. Migratory birds start arriving in the month of October. They include a variety of Geese, Ducks, Raptors, Geese, Warblers and Waders.
 
Extending over an area of 800 sq km, the Sariska Wildlife Sanctuary is located in the forest hills of the Aravalli ranges in the state of Rajasthan. It provides habitat to more than 200 species of birds including the Gray Hornbill, Crested Serpent Eagle, Black/Red Headed Bunting, Wryneck Woodpecker Babbler, White Breasted Kingfisher, Little Brown Dove, Small Minivet, Golden Oriole, Great Gray Shrike, Pale Harrier and Tailor Bird. An example of typical dry deciduous forest, the sanctuary remains lush and green during the monsoons and dry during the rest of the seasons.
 
Other place is the Pong Dam reservoir is 65 km Pathankot and 115 km from Dharamsala. Nestled in the sylvan surroundings of the Kangra valley, the sprawling Pong Dam wetland has emerged as a major habitat for migratory birds in the country as also an attraction for bird watchers. The most common bird species that have arrived and often visit this lake every year include ruddy-shell ducks (surkhab), bar-headed geese, mallards, coots, pochards and pintails besides rare red-necked grebe and gulls. These species come from as far as China, Siberia, Central Asia, Pakistan and Ladakh. According to a census, more than one lakh migratory birds visited the lake last year.
 
Apart from being home to the tiger, Corbett National Park is also noted for the bird watching. Considered to be one of the best bird watching sites in the world, the park is home to some 600 species of birds. This number exceeds the total number of bird species found in Europe and is about one fourth of the diversity found in India. A case in point is that out of the 69 species of raptors found in India, 49 can be seen in Corbett. Spreading out on an area of 520 sq km, the Corbett National Park is a hot destination for bird-watchers. Bird-watchers from across the world make a beeline to this park during winters when the bird diversity is at its zenith.

 

Painted Storks – Pic by Geeta Shankar

Threats and conservation

Human activities have threatened many migratory bird species. The distances involved in bird migration mean that they often cross political boundaries of countries and conservation measures require international cooperation. Several international treaties have been signed to protect migratory species including the Migratory Bird Treaty Act of 1918 of the US and the African-Eurasian Migratory Waterbird Agreement.The concentration of birds during migration can put species at risk. Some spectacular migrants have already gone extinct, the most notable being the Passenger Pigeon (Ectopistes migratorius). Other significant areas include stop-over sites between the wintering and breeding territories. A capture-recapture study of passerine migrants with high fidelity for breeding and wintering sites did not show similar strict association with stop-over sites.Hunting along the migratory route can also take a heavy toll. The populations of Siberian Cranes that wintered in India declined due to hunting along the route, particularly in Afghanistan and Central Asia. Birds were last seen in their favourite wintering grounds in Keoladeo National Park in 2002.Structures such as power lines, wind farms and offshore oil-rigs have also been known to affect migratory birds. Habitat destruction by land use changes is however the biggest threat and shallow wetlands which are stopover and wintering sites for migratory birds are particularly threatened by draining and reclamation for human use.

Refereces: Salim Ali ‘The book of Indian Birds’, Wikipedia, Indian Wildlife.htm, HSBC’s Environment Forum

MY BLOG LIBRARY

For some of my articles visit:

http://mohanpaiblogger.blogspot.com/http://mohanpaisarticles.blogspot.com/http://biodiversity-mohanpai.blogspot.com/
For some key chapters from my book “The Western Ghats”, please log on to:http://westernghats-paimohan.blogspot.com/

For detailed blog (6 Chapters from my book) on Mahadayi/Mandovi River Valley, please log on to:http://mohan-pai.blogspot.com/

For the book ‘The Elderly’ please log on to:

http://oldagecare-paimohan.blogspot.com/
http://omashram.sulekha.com/blog/posts.htm
You can also access my blogs on Sulekha and WordPress:
http://mohanpai.sulekha.com
https://mohanpai.wordpress.com/

For my book “The Flight of Gods – Hindu Temples & Shrines of Goa” please log on to:
http://flightofgods.sulekha.com/blog/posts.htm
http://flightofgods.blogspot.com/

Vanishing Species – The Painted Stork

An article by Mohan Pai

 

The Painted Storks of Veerapuram & Kaggaladu

Pic by Geeta Shankar

These migratory birds are endangered species who find a haven in the understanding and caring villagers.

Last week April 22-23), we made a trip to two heronries of painted stork near Tumkur. The first site we visited was Kaggaladu village near Sira and the second nesting site, a village called Veerapuram, just across the border in Andhra Pradesh. Karnataka (Kokrebellur, Rangantitthu, Kaggaladu etc.) and Andhra Pradesh ( Kolleru Lake, Pulicat, Neelapatu, Veerapuram, etc.} have sizeable colonies of these migratory birds.

These birds are thought to have migrated originally from the Great Russian ice desert in Siberia. They went south towards Asia, seeking warmer and more comfortable places of the world like India, Sri Lanka, Thailand and Malaysia. However, they seemed especially drawn to the Indian Peninsula. They come to breed in and around large bodies of water and coastal areas.

Standing from a distance, heronries of painted storks look like cluttered dirty blobs of white on the tree tops. One really has to strain his eyes to make out what exactly the entire scene represents. A closer look brings in view spectacular ‘hunched up’ colony of large birds. Built on tree one might find as many as 10-20 nests on a single tree, almost touching each other.
Painted Stork is a massive bird with a yellow, long and heavy bill, slightly curved near the tip. The plumage is white and closely barred, marked with glistening black above and with a black band across the breast.

Veerapuram

Statue of two painted storks adorn the entrance to Veerapuram Village – Pic by Geeta Shankar

It’s wonderful but difficult to understand the bond between the painted storks from Siberia and Veerapuram, a tiny remote village in Anantapura district, about 140 km from Bangalore. The Painted Storks have settled down in Veeepuram for more than a century now. The chemistry of love between the storks and Veerapuram is unfathomable as the birds are found nestled only on the trees within the village and not even on the outskirts.

Idyllic scene – Veerapuram Village – pic by Geeta Shankar

The villagers claim it is their “love for the guest birds” which keeps them in the village. Though the village has a small water body (a tank) it dries up by the time the guests arrive in the village or it doesn’t get the water at all due to the poor rainfall in the area. Nestled in the village the male birds fly even up to a couple of hundred km every night to fetch food from the water bodies. However, they return to the nests by dawn. The painted storks from Siberia and Algeria fly across the seas and mainland for about 6,000 km to reach Veerapuram. The migration starts from December and ends in May-June when the birds return to their homelands along with their new borns.

They start hatching immediately after reaching the tropical areas. After a gap of four years, an estimated 2,500 birds have migrated to the village last year. The villagers see the war in Afghanistan and severe drought conditions in the district for the last four years as the reason for the absence of the guests in the recent years.

The young chicks often fall down to the ground from their nests and are injured. The caring villagers have set aside a nursing hut for these injured birds. A vet is called in to treat the sick.

Chicks fallen to the ground are being nursed by the villagers – pic by Mohan Pai

It is amazing to see and know that these birds have chosen this village as their breeding centre. It is presumed that because these villagers take care of the birds by not harming them, they repeatedly come every year. The Care and concern shown to these birds by very enthusiastic children and the old of the village was very evident. We saw a big net which was tied under the trees to safeguard the eggs from falling onto the road.

Enthusiastic youngsters of Veerapuram

There are some 20 tamarind trees full of painted storks. But we also found a nest (above) in a gulmohar tree! – pic by Geeta Shankar

Feeding ground – A lake near Veerapuram Pic: Mohan Pai

Kaggaladu

Kaggaladu village near Sira, about 128 km from Bangalore, has become a potential bird sanctuary. The birds first started nesting here about 12 years ago. Around 10-12 tamarind trees turn into home for the painted storks from November to May every year. The painted storks come here in November from far away Pakistan, Bangladesh, Bhutan and Sri Lanka. Kaggaladu Village – pic by Geeta Shankar

The villagers treat the birds as family members and never pluck the tamarind as it would disturb the nest. Every villager has turned into an ornithologist and they have a good account of the life-style of the birds. Adding to the presence of the painted storks there is a sizeable population of grey herons. There are also some Spot billed pelicans around.

However, Kaggaladu is in need of serious sustainable conservation effort to maintain itself as one of the most important breeding sites for Painted Stork.These large beautiful birds prefer Tamarind trees for nesting, completely avoiding all other trees. Probably the strong stunted branches of Tamarind provide an easy landing for these heavy birds. More over, having no dense foliage, tamarind trees offer relatively lower resistance against stiff wind, which is prevalent in this part of Karnataka. This makes the nesting places safe from dangerous sway. Even though we could see many tamarind trees in the village, the storks choose only 10 of them for reasons completely unknown. Apart from the fact that the villagers take care of the trees, there is no coordinated effort to protect them. Four of the five nesting trees are on government land, by the road and the other one is on private land. We have seen private buses irresponsibly honk their horn loudly and race through the village road directly below the nests.

Painted stork colony in tamarind tree – pic by Geeta Shankar

The tank and its vicinity however, had gone dry in the last four years due to incessant drought in the area. It was yet another reason why nesting activity had come to halt. Birds used to come and leave soon after noticing the dry tank. The tank received some water during the rainfall in September-October year before.

Physical Traits

The Painted stork of India is a tall and slim bird, which grows to a height of 95 to 100 cm. The bird is mostly white in color, with the exception of its wings and chest feathers that have black and white markings. The color of the lower back, along with the legs, is light pink. The head of the Painted storks is only partly covered with feathers and is orange in color.
The bill is long, yellow in color and curves towards the end. The female Painted stork is a little smaller than the male. The young ones are brownish in color when they hatch. Only after they become three years old, do they get adult feathers or plumage. Full maturity comes around the age of four years.

Diet

Painted storks of India prefer to eat fish, which also forms a major portion of their diet. However, at times, they consume frogs and snails also. When hunting, the stork puts its head inside the water, with its bill being partly open. The bird keeps swinging its head back and forth in the water, till it catches a prey.

Natural Habitat

Painted storks are seen occupying Indian freshwater marshes, ponds and flooded fields. Apart from India, the bird is found in Pakistan, Sri Lanka, eastern China, Kampuchea and Vietnam. A small population of the Painted stork lives in Thailand also.

Status

Painted stork bird of India has a place in the list of protected species, at the moment.

Predators

The predators of Painted stork of India include tigers, leopards, jungle cats, hyenas and crocodiles. Some villagers also kill them for their meet.

Behavior

Painted Storks are found mostly in large colonies and stay near water. The nests, made up of sticks and leaves, are built close to the edge of the water. One can see other stork species, like herons, ibises, cormorants and spoonbills, sharing the habitat with Painted storks. Till 18 months of age, the young ones can make loud calls to attract their parents. However, after this, they lose their speech and use other signals to convey something to their fellow birds.

Mating Behavior

The breeding season of the Painted stork starts towards the end of the rainy season. The mating period is the time for the male storks to perform ritualistic displays and attract females. After mating, the nest is built and the female lays around 3 to 5 eggs. The incubation period is between 27 and 32 days and the responsibility is shared by the both the parents. The young ones become fully matured when they attain four years of age.

Senses

The most important as well as the most developed senses of the Painted stork comprise of its eyesight and hearing. The young ones communicate through loud hoarse call. However, after attaining 18 moths of age, the style of communication changes to clattering of large bills or hissing or bowing to each other or spreading the wings, etc.

References: Wikipedia, Deccan Herald, Hindu, Indian Express.

Acknowledgements: My grateful thanks to Mrs. Geeta Shankar, Mr.Chandrappa, RFO, Sira Division, and Mr. Gurumurthy of Karnataka Forest Dept.


Blog Stats

  • 64,549 hits

Top Clicks

  • None

Flickr Photos

Top Rated