Watching flocks of migratory birds has been an ancient pastime and the mystery of “Why” and “How” these birds come to the same place time after time is fascinating. “How do they know where to go and when to go?” is an oft asked question among people as they sight the arrival or departure of migratory birds.
It has now been discovered that these routes may be genetically programmed into the birds or else it was learned and mastered over the years of flying.
Bird migration can be broadly defined as a seasonal journey undertaken by birds. They make this journey for climate, food availability and habitat especially when winter closes in. With the approach of winter, in many countries day light wanes and birds find it difficult to feed.
Food is important to have a healthy reproductive system. So, they fly to warmer climes, feed well and when they know that it is time to fly back home, they leave. This is the reason why migratory birds do not build nests and breed in their host country.
Flying in
Theodore Baskaran, a noted Birdman says, “Birds use migratory flying corridors known as “flyways”, that span many continents, mountain ranges, rivers and coastlines. Research into their migration routes shows that they avoid geographical barriers and large stretches of water, just like aviators.”
They come from East Europe and from the Himalayas mainly during the winter season.
It has been found that birds fly at different altitudes during their long journey. According to an expedition team in the Himalayas, skeletons of the pin-tail and Black-tailed godwit and Bar-headed goose have been found in the Himalayas. It is said that sea birds fly low over water and rise to a greater altitude when over land.
Resident migratory birds build nests and breed in India, whereas migratory birds come visiting in search of food.
“Another special feature is the breeding plumage. When they are flying in, they are normally dressed in rather drab colours. During breeding time, they are decked up in flamboyant colours,” says Mr. Thirunaranan, of Nature Trust, Chennai. He points out that Vedanthangal and Koodankulam in South India are hospitable places for the birds with regard to food and breeding.
The Bar-tailed godwit is known for the longest known non-stop migration of any species — it flies up to about 10,200 kms.
About 3,000 years ago bird migration was recorded by Greek poetslike Homer, Hesiod and Aristotle, in their poems. Muththappulavar, a poet from Madurai, wrote about the migrating white storks known as — Valasai, 2000 years ago . He addresses them as “Naarai’ and sends a message through them to his wife who lived in Kumbakonam.
The Bible too has references to bird migration.
“Does the hawk take flight by your wisdom and spread his wings toward the south?” (Job 39:26)
Symbiotic relationship
Kokkara Bellur in Karnataka is called a two-tier village, where humans live at one level and birds at the other. Khichan in Rajasthan feed cranes and Koodankulam, a village near Tirunelveli, plays host to birds. So firecrackers are not burst and drums are not played during events.The villagers feel that the birds are harbingers of luck and the bird guana (excreta) nourishes their fields.
Flying in
World Migratory Bird Day (WMBD) this year was on May 10-11. It stresses the importance of conservation and creates awareness on the need to protect migratory birds. Especially while it is on its route and its various habitats. This year, the theme for WMBD is: “Destination Flyways: Migratory Birds and Tourism.”
This theme links three factors — key migratory bird sites, local communities and tourism.
Water birds
The Point Calimere Wildlife and Bird Sanctuary in the Nagapattinam district, in South India, is a meeting place for migratory water birds in India. In October, these water birds arrive from the Rann of Kutch, Eastern Siberia, Northern Russia, Central Asia and parts of Europe for their feeding season and begin their return journey in January.
These water birds include threatened species such as Spot-billed Pelican, Nordmann's Greenshank, Spoonbill Sandpiper and Black-necked Stork. Near-threatened species include Black-headed Ibis, Asian Dowitcher, Lesser Flamingo, Spoonbill, Darter and Painted Stork
Researchers at The Bombay Natural History Society have studied, ringed and released over 2,00,000 birds during their ornithological studies.
Be a good host
However, all is not well in the avian world. Climate change and global warming have played a heavy hand and there are cases of overstays. Another serious problem faced by migrating birds is that of poaching and hunting on their stopovers. For example, the population of the Siberian Cranes declined due to hunting when they broke journey in Afghanistan and Central Asia. According to reports, these birds were last spotted at the Keoladeo National Park in 2002.
Visitors of any species are a joy to have around. We, as hosts must make it our responsibility, that they are treated well before they leave, whether they be two-legged or feathered. Can you imagine a world without the varied colours of our migrant- feathered friends?
