Sunday, 4 December 2011

PICTURES OF MIGRATORY BIRDS IN INDIA





Waterfowls Species


birds that arrive in Indian plains



from Bhubaneswar, India

Flamingo

Sparrow

Migratory birds seen at the National Zoological Park in New Delhi, India

Migratory birds in Bharatpur, Rajasthan, India

from Lake Kolleru

 Migratory birds, Chatrapati Shahu Maharaj Palace Lake, Kolhapur

from Nagpur



Kumarakom Bird Sanctuary, Kerala, India

DANGER OF BIRD FLU


These days, people are talking about the danger of bird flu from these migratory birds, like the recent finding of some carcasses of birds such as red legged falcon in Tamenglong and Senapati districts of Manipur.

              It is understandable to think that migratory birds can possibly bring the virus from very far off countries to our state because of their long distance flights. However, we must not go hysterical about these migratory birds (unnecessarily blaming the birds for carrying the virus); though we need to be alerted about the danger being caused by bird flu (because sometimes it can kill people).

              Because the danger comes the moment the virus changes to one that can transmit between humans. Then the clock starts ticking. Currently, the WHO puts the danger level at 3 whereas the pandemic level (worldwide epidemic level) is 6.

              It has reported from reliable sources that people have handled dead bird without getting sick. Cooking easily killed the virus. Eating cooked chicken or egg is not dangerous. The disease may be transmitted from birds to human, but the danger of infection is quite low. 

HOW DO THE BIRDS MANAGE TO MIGRATE?

             How do they manage to do this? Most birds have remarkable memories and are good at "pattern recognition". Migratory birds usually fly using the position of stars, the sun, and star patterns. Birds also, of course, use landmarks, such as rivers, mountains ranges, coastlines seen during previous journeys as path guides.

            But the most important environmental cue the bird used during its migration is the earth's magnetic field. Birds can measure the angle between the magnetic lines that surround the earth and the vertical direction of gravity; and take bearings from this 'magnetic dip'. The value of the magnetic dip at the nesting site is perhaps imprinted in the bird brain.

On its way back home after the winter sojourn, the bird flies in a direction which brings it closer to and ultimately exactly to this figure. 

PRESENT SITUATION OF THE ISSUE- 'MIGRATION OF BIRDS'

         In India, bird migration has been studied by the BNHS (Bombay Natural History Society) intermittently since 1980's. So far 4 lakhs birds have been ringed or banded; but the recovery rate was very low (only 1%) and no conclusion on the migration of birds in India can be inferred. Most data on the migration of birds in India comes from many developed countries such as Japan, European countries, the USA, etc.

            Recently, one black kite Milvus migrans lineatus ringed in Mongolia in its nest on July 18 2001, by Michael Stubbe from the University of Halle, Germany was captured live near Loktak Lake in Manipur on October 22, 2001. This is perhaps the first concrete evidence of migration of black kite from Mongolia to India and provides the information that black kite is a winter visitor in Manipur, NE India.

            Millions of birds annually travel between their nesting sites in the northern hemisphere and their wintering ground in the southern hemisphere. The most amazing aspect of this bird migration is the bird's return to its location faithfully with pinpoint accuracy. 

Bird migration is still a mystery to the scientists.

Questions such as 'Why do birds migrate?' and 'How do birds migrate?' still evade exact explanations. The phenomenon of migration is mostly or always directed from north to south. This idea led some to believe that bird migration is an inheritance of acquired characters.

During Ice age, about 2 billion years ago, the northern hemisphere of the earth was just inhabitable and many birds of the areas migrated towards south in search of more hospitable habitats. Such characters remained acquired and inherited even after the end of Ice age, and bird migrations continue till today.

Birds used many environmental cues for its migration for they have to know 'where to migrate', 'when to migrate' and 'how to migrate'. Photoperiod tells birds when to migrate. Birds start preparation for migration at certain period of particular day length.

Just before migration bird usually starts deposition of fats in their body. When this fat deposition reaches certain level, the birds begin to feel restlessness (which is called Zugunrunhe in biological term) and start migrating. The body fats provide energy during the migration. Many migrating ducks fly in an enchanting V-formation, which has a good aerodynamic interpretation or significance in the sense that the ducks by flying in this formation save a lot of energy.

Birds used certain flyway zones for its migration, for example, Indus Valley flyway zone and the Brahmaputra river valley flyway zone in the Indian subcontinent. But some birds fly directly across the high Himalayan Mountains.

Thus it seems that there is no imperation that birds would use one route though the Indus Valley flyway zone is one of the most popular routes among migratory birds coming to India.
 

EXAMPLES OF MIGRATING BIRDS IN INDIA


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.

Migratory Birds Coming to India in Winter Season
  • Siberian Cranes
  • Greater Flamingo
  • Ruff
  • Black winged Stilt
  • Common Teal
  • Common Greenshank
  • Northern Pintail
  • Yellow Wagtail
  • White Wagtail
  • Northern Shoveler
  • Rosy Pelican
  • Gadwall
  • Wood Sandpiper
  • Spotted Sandpiper
  • Eurasian Wigeon
  • Black tailed Godwit
  • Spotted Redshank
  • Starling
  • Bluethroat
  • Long billed Pipit
Migratory Birds Coming to India in Summer Season
  • Asian Koel
  • Black crowned Night Heron
  • Eurasian Golden Oriole
  • Comb Duck
  • Blue-cheeked Bee Eater
  • Blue-tailed Bee-Eater
  • Cuckoos

MIGRATION OF BIRDS IN INDIA


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. The numerous wildlife sanctuaries set up in the country serve as their temporary habitat. Bird lovers from all over the country visit these sanctuaries to get a glimpse of some of the rarest species of birds in the world. The beauty of the birds, combined with the splendor of the natural environment provides the perfect setting for a nature lover.

Usually, birds start migrating towards other areas when they perceive the tailwind to be favorable. However, once they start their migration journey, nothing can stop them, except extremely bad weather. Many birds prefer to fly at a higher altitude while migrating. 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.