It is delightful indeed to watch a flock of ducks flying gracefully in the air. Especially the migrant birds which travel thousands of kilometers to reach India. Some migrants cross the Himalayas to reach here . Will we continue to see them year after year ?
Avid birders always look forward for the arrival of migrant birds . For all birds, one of the main driving force behind migration is food scarcity. If all birds were to stay in the same tropical regions through the year, food would become scarce and breeding would be less successful. But as food sources regenerate in the north each spring, millions of birds migrate to those areas to take advantage of the abundance. As food supplies dwindle in the fall, they return to replenished tropical regions.
Climate change is another key reason. Many birds leave Arctic breeding grounds when temperatures begin to dip and they need more temperate habitats. Similarly, the hot tropical regions can be harsh for raising chicks, and it is advantageous to lay eggs further north.
In the year 2008 Sudhir Shivram had reported that Hebbal Lake had hundreds and thousands of northern shovelers and a lot of other birds. Ref
“In 2012 Waterfowl survey the migrant ducks neither the Northern shovelors nor the pintails were found in the Hebbal lake.” says Sheshadri K.S an avid birder
From the above quotes it is evident that In 4 years thousands of ducks which were visiting Hebbal lake are not visiting anymore.
Answering a query whether there has been a decline in the number of migratory birds visiting Bangalore , ornithologist MB Krishna says ” I think so , given the drastic loss of habitats in bangalore. even for species globally, the single largest cause for species loss is loss of habitats. We used to count around a lakh birds in around 80-100 sites in january within a 40km radius of the GPO. Doubt whether one could do it now! ” .
Some winter visitors of Bangalore – Hoskote
The White Stork (Ciconia ciconia) is a large bird in the stork family Ciconiidae. Its plumage is mainly white, with black on its wings. Adults have long red legs and long pointed red beaks. They rely heavily on energy efficient soaring flight during migration. Soaring requires the presence of thermal air currents that are not found over water. White Storks are therefore reluctant to fly across large bodies of water such as the Mediterranean Sea to reach their wintering grounds in tropical Africa. Migration is highly synchronized and flocks contain as many as 11,000 individuals.
Wintering birds may congregate in large numbers as they utilize a locally abundant food source such as locust or grasshopper swarms. These wintering birds occupy open grasslands but tend to congregate around lakes, ponds, and rivers. Breeding White Storks prefer lowland open habitats of wet pastures, flooded meadows, and shallow lakes and marshes with scattered trees for roosting and nesting. They have adapted to nest on man-made structures and forage in freshly plowed fields.
Northern Pintails are slender ducks, having long sharp tail . These aquatic birds are at ease on both water and land where they often forage with their uniquely built mouth. Their streamlined bodies help them fly long distances during migration at great speed.
During winters they can be traced to a number of locations in tropical regions of South Asia, Africa (northern sub-Sahara) and Panama. Northern Columbia, Central America and regions in the Caribbean are regularly visited during the winters.The Northern pintails migrate to India every year, by the month of September and stay till March. During the winters, they are heavily spotted in different northern parts of India. It has been reported that these birds cross the Himalayas to migrate .
This bird winters in southern Europe, Africa, the Indian Subcontinent, northern South America, and the Malay Archipelago.Those wintering in the Indian Subcontinent make the taxing journey over the Himalayas, often taking a break in wetlands just south of the Himalaya before continuing further south to warmer regions. The most unique feature of the northern shoveler is its large shovel-shaped bill. Male shovelers have green heads, a white body, rusty-red undersides and black wings. Females have mottled brown, black and white feathers and a blue patch on their wings. They feed primarily on small invertebrates and seeds. They rarely forage on land, and are most easily seen on the water using their bills to strain the water for food. This species may also be observed undertaking straight, swift flights on migration or between breeding or foraging grounds. These birds are most active during the day.These dabblers also tend to be monogamous. They will stick to one mate at a time and will tend to remain in pairs for long periods of time.
A flock of Garganey ducks
The Garganey (Anas querquedula) is a small dabbling duck.The adult male has a brown head and breast with a broad white crescent over the eye. The rest of the plumage is grey, with loose grey scapular feathers It has a grey bill and legs. In flight it shows a pale blue speculum with a white border. When swimming it will show prominent white edges on its tertials. His crown is dark and face is reddish-brown. It breeds in much of Europe and western Asia, but is strictly migratory, with the entire population moving to southern Africa and Australasia in winter, where large flocks can occur.
Glossy ibis is a dark wading bird with a long, down-curved bill. Glossy Ibises are threatened by wetland habitat degradation and loss through drainage, increased salinity, groundwater extraction and invasion by exotic plants.
Over the years, the arrival pattern of migratory birds in India has constantly been on a decline. During December several birds from the colder regions are spotted at several places in the country. Small birds like flycatchers arrive in early November. Wagtails usually arrive in mid-October. Ducks come by end of October or early November in huge numbers. Changing crop pattern, use of pesticides and loss of habitat have led to loss of as much as 80 per cent of migratory birds’ arrivals to the wetlands of the country. Loss of habitat is a bigger deterrent. Agricultural pesticides enter water habitats and they are also filled up for construction. Both the things have affected bird migration.
Presently, due to the global warming the departure dates of many of the migratory species are postponed and this has an alarming significance because the food cycles and arrival times of migrants in the tropics do not coincide. The migratory birds in India may find the important source of food becoming scarce.
“Nature conservation through education can help get us back the lost numbers of migratory birds in India. “Importantly we should identify the habitats and places where migrants arrive and protect them. We should educate local people and children about the various facets of bird migration. Unless the common man is sensitized conservation shall be ineffective. The grass root level effort shall yield results. Hunting should be stopped. Use of inorganic pesticides alone should be reduced by supplementing organic pesticides. The bio-control of pest by promoting the usefulness of natural predators should highlight,” Pande, who has founded ELA Foundation, an organisation devoted to nature conservation through education said.
If we can picture a world in which there’s no seed dispersal, pollination or pest control naturally done, then we’d be picturing a world devoid of bird species which do the planet an essential ecological service. In fact, studies done as to the cost of such services provided by nature to humanity (by insects, birds, plants) were estimated in a 1997 study to be 30 trillion dollars, according to Harvard University Professor Emeritus, E. O. Wilson (from the BBC Planet Earth series, “Saving Species” fragment).
“In the case of migratory birds, if we consider their stopping to feed and breed in particular regions in perfect timing with the massive hatching of worms, or any other insect, we have a natural pest and parasite control in these winged pilgrims. And, at the same time, these birds may be essential to nourish other creatures in the same ecosystem, essential predators at a higher level of the food chain. The arrival of these birds to their breeding grounds, the eggs they produce and eventually their nestlings, are an essential source of food for small predators to feed on and to nourish their young. A disturbance in the population and arrival timing of migratory birds would entail problems for all predators that await this annual food bonanza.” Ref
Whether these agile, strong and beautiful birds will continue to visit us actually depends on us. And it is on us to protect the ecosystem so that migratory birds in India can come and delight us.
Photo credits : A.S.Kannan