If one is interested in migrant birds, the ideal time to look for them is during the last two months of the year, by mid-November, the majority of our wintering birds may have arrived in our shores. The migrant birds generally start arriving here late in August and early September. When the cold wind from the Bay of Bengal begin to blow over, heralding the onset of the North-East monsoon. But it will not be until October and November that the main influx takes place. During these two months large number of winter birds arrives from their breeding haunts in the dist and part of Asia and Europe.
There are nearly 427 species and sub-species of birds in Sri Lanka today and of them approximately 176 are migrants. And, except a few species of oceanic birds, all of them fall in to one category – winter visitors.
From which parts of world do these migrants birds come and how? What are there migratory routes? These are but a few of the questions posed by amateur bird watchers. Detailed studies carried out by ornithologists in this country an elsewhere have revealed that majority of migrant birds found in Sri Lanka come from countries situated within the temperature zone.
Almost all migratory waders seen here during the North-East monsoon have breeding grounds in the Steppes and Tundra, north of Asia and Europe. Such birds as the Turnstone, Marsh Sandpiper, Sanderline, Long-tailed Stint and Caspian Plover may Sri Lanka from breeding grounds in Northern and Southern Russia or from places within the Arctic Circle.
The Great brown-headed Gull and the Herring Gull; which occasionally visit our coastal lagoons, definitely come from large lakes in central Asia and from Russia, including Siberia, while their smaller relative, the Whiskered Tern comes here from inland lakes in Kashmir.
The Pintail, Garganey, Shoveller and Gadwall are some of the wild Ducks most of us will know may have seen some time or other. But how many of us actually know the great distance they fly to reach the warmth of our shores? The vast majority of them come from countries far North of Asia and Europe, and a few from Tibet and Mongolia. The commoner snipes – pintail and fantail-hail from places situated thousand miles apart. The first comes here from the East Siberian marshes and other from Northern European countries, Japan and northern China.
The migratory Warblers (as many as eleven are known) almost certainly come from breeding grounds in Eastern Europe and Northern Asia. While a couple of Warblers come from Afghanistan, Kashmir and the Himalayas, the Blue-Chat, Pied Ground Thrush, Northern Orange Headed Ground Thrush and Indian Blue Rock-Thrush come solely from Himalayan foothills.
So do some of the migratory flycatchers, i.e. Blue-throated Flycatchers, Brown Flycatchers and the Layard’s flycatcher. It is certainly that the Indian White Wagtail, Eastern Gray wagtail and the yellow-headed Wagtail too come from the Himalayan nesting grounds.
The Indian plaintive Cuckoo and the Asian Common Cuckoo certainly breed in the same localities as the flycatchers, and used the same routes along the west coast to reach Sri Lanka.
The Hawks and Eagles encountered in the island during winter period come from a variety of countries in Asia and Europe. The Siberian Honey Buzzard has its headquarters in Eastern Siberia, while the Desert Buzzard comes from Japan or perhaps from Burma.
The four species of Harriers occur in the island have been traced to breeding grounds in northern parts of Asia and Europe.
The Osprey and the short-eared Owl are birds of the Temperature Regions. The rarer Red-legged Falcon arrives from breeding places in the North East of Asia and the Kestrels fly in to Sri Lanka from Western European countries, Japan and Northern China. The Purple Wood Pigeon obviously comes from Bengal Indo-China and the two migratory Turtle Doves have their nesting haunts from the Himalayas and Central Asia.
The Black-capped Kingfisher and the Tiger or Malay Bittern are considered rare migrants whose nesting grounds have been traced to Western Sumatra, Burma and Malaysia to China.
The bird watcher countrywide looks forward to the arrival of the Eastern Swallow than the other migrant birds. It is one of the first to appear in our shores, scattered flocks having been seen here as early as the third week of August.
The Eastern Gray Wagtail, perhaps the commonest and the most welcome visitor in the Central Hill Zone, may be another forerunner in the long train of winter visitors in our country immediately on arrival in the Island it be takes to the hill country and as a result its first arrival is hardly recorded in the low-lands.
The Sandpipers, Stints, Curlews, Golden Plover, too arrive in the late August or early September. Many of the smaller passerine birds start to arrive in the late September or October.
The Pintail Snipe comes in from September. The ducks, teal and other wild fowl are surely the last to start on their migratory journeys, which can be judged from the vast flocks that appear in Sri Lanka during November and December.