Migration in Birds


Siberian Crane (Grus leucogeranus). The Siberian Cranes nest in Yakutia and western Siberia of Russia and migrate to India. The migration route stretches for 4000 miles. Their resting place at the time of migration is the Lake Ab-i-Estada in Afghanistan.

The Kaladeo Ghana National Park or the Bharatpur National Park has been declared a world heritage site because the Siberian Crane traverses nearly half of the globe to reach it. The eastern population winters on the Yangtze River and Lake Poyang in China, the central population at Keoladeo National Park, India (the last Siberian Crane in this population was observed in 2002), and the western population in Fereydoon Kenar in Iran. It breeds and winters in wetlands, where it feeds on the shoots, roots and tubers of aquatic plants.

Ducks, shovellers, teals and geese. Some duck species, mainly those breeding in the temperate and Arctic Northern Hemisphere, are migratory; those in the tropics, however, are generally not. Some ducks, particularly in Australia where rainfall is patchy and erratic, are nomadic, seeking out the temporary lakes and pools that form after localised heavy rain.

Black-headed bunting (Emberiza melanocephala).The males are quite gorgeous with their black heads, brilliant yellow underparts and rich reddish-brown upperparts. The females are much duller although they often show at least a hint of yellow, especially on the undertail coverts and the head is usually distinctly darker than the throat, creating a hooded effect which mimics the pattern of the male. Migratory, wintering in western and central India. Arrives in the breeding areas in late April or May and departs in July or early August.

Black poll warbler (Dendroica striata) is a New World warbler. These birds breed in northern North America, from Alaska, Canada, and up to New England and winter in north-western South America. Part of their fall migratory route is over the Atlantic Ocean from the north-eastern United States to Puerto Rico, the Lesser Antilles, or northern South America. This route averages 1,864 miles over water, requiring a potentially non-stop flight of up to 88 hours. To accomplish this flight, they nearly double their body mass and take advantage of a shift in prevailing wind direction.

Humming birds. Most hummingbirds of the U.S. and Canada migrate south in fall to spend the winter in northern Mexico or Central America. Ruby-throated hummingbird flies 600 miles across the Gulf of Mexico in 25 hours non-stop. A few southern South American species also move to the tropics in the southern winter. A few species are year-round residents in the warmer coastal and interior desert regions.

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.

BIRD NAVIGATION

Birds use a number of methods to find their way during migration. Many use celestial navigation, a method of orienting the body to the arc of the sun, to the phases of the moon, or to the pattern of the stars in a particular season, which is called menotaxis. Others, such as hummingbirds and pigeons, are able to determine the position of the sun even on overcast days because they can detect the ultraviolet radiation it emits.

Experiments in planetarium on night migrant birds, such as white throated warblers and indigo buntings reveal that they orient themselves by the position of stars in the night sky.

Some birds are sensitive to coriolis force that arises by deflection of winds in the northern hemisphere by earth’s rotation.

Some diurnal birds use topographical landmarks such as mountains, river valleys, and forests to orient themselves on the migration route. Some are able to detect infrasound or low-frequency sounds that are produced by pounding of the ocean surf that travel long distances and are detected by birds. Many birds, particularly seabirds, identify their destinations by characteristic odours.

Many birds possess instinct or some kind of internal compass or biological clock that guide them to the route of migration. Young birds follow the migration route accurately without previous training or experience.

Some birds such as oil birds of South America possess echolocation and can be guided by it.

The classic experiment proving the internal-clock theory was done by German Gustav Kramer during the early 1950’s. He placed caged Starlings wanting to migrate so they could see the sun. The birds would sit looking in the direction toward which they wanted to fly. Significantly, if the Starlings couldn’t see the sun, they didn’t face in any particular direction.

Also during the 1950’s, the German Franz Sauer did a similar experiment with birds that could and could not see the night stars. The results were the same: Certain species can orient themselves according to the sky’s major stars. In fact, an experiment with Mallard Ducks found that if the moon is so bright that important stars are hidden by glare, released ducks can’t orient themselves as well as on darker, moonless nights.

Some birds, such as pigeons, are sensitive to changes in the earth’s magnetic field and to gravity because of magnetite they possess in their head and neck muscles. During the early 1970’s, W.T. Keeton did a series of elegant experiments to get the answer. He glued small, non-magnetic brass bars on the backs of pigeons and on the backs of a similar group he glued miniature magnets which, he thought, might disrupt the Earth’s magnetic field in the vicinity of the pigeons. When released at locations the birds had never seen before, the pigeons with non-magnetic brass bars found their ways home much better than those with magnets on their backs.

In a 2007 article in the German journal Naturwissenschaften scientists announced that they’d found tiny iron oxide crystals in the skin lining of the upper beak of homing pigeons, laid out in a 3-dimensional pattern in a way that the birds might be able to sense the Earth’s magnetic field independent of their motion and posture, and thus identify their geographical position.

The researchers discovered molecules called cryptochromes, which change their chemistry in the presence of a magnetic field, in the retinas of migratory birds’ eyes. When light hits these molecules, their chemistry changes and magnetism can influence them. The molecules might then affect light-sensing cells in the retina to create images, which would help the brain navigate during flight.

Infrasound travels much farther than ordinary sound and it comes from many different natural sources, including ocean waves, surf, winds, storms, earthquakes and other geologic events. If you can hear infrasound, you can listen to the whole world.

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