Although Nepal covers only a fraction of 1 per cent of the earth’s land mass, it contains over 800 species of birds, about a tenth of the world’s known birds, and of these more than half are found within the national park. The reasons for Nepal’s great wealth of birds are mainly topographical. First, the country has a huge variation in altitude within a short lateral distance, so that conditions range from tropical to arctic in a distance of less than 100 miles; and second, Nepal lies in the region of the overlap between the Palaearctic realm to the north and the Oriental to the south.

Chitwan, with its dense forests, grasslands, rivers, swamps and lakes, provides a multitude of habitats for birds. Each provides a different type of food and shelter. Even within the same habitat, different birds feed selectively, minimizing competition for food. The Park is a paradise for birds and birdwatchers alike.

Many birds are regarded as residents because they live in the Park all year round; others visit only in summer, often to breed. Another group are the winter visitors which descend from mountainous regions to spend the cold months in a more hospitable climate. Migratory birds also use the Park during spring and autumn when resting on their journeys to northern breeding grounds or southern wintering areas.

Possibly the most spectacular of all Chitwan’s birds is the common peacock. His brilliant plumage and magnificent tail, particularly when it is erected into a great circular fan during courtship displays, are an impressive sight. In spite of his long, trailing tail, the peacock often flies into tall trees, announcing his presence with a loud, trumpeting call. Groups of the comparatively drab, gray-brown females are often disturbed in grassy areas near forest edges as they search for insects, small snakes and geckos, fruits or green shoots.

Its seems remarkable that well over half of the birds listed for Nepal should be found here, the reason is that the park’s heterogeneous environment provides a multitude of ecological niches for birds to exploit. For instance, the river systems and associated bodies of water contain a wide assortment of aquatic fauna and flora, while the forest and grasslands provide flowers, nectar, fruits and seeds, as well as the ubiquitous insects.

Chitwan supports a poor population of fishing raptors. All the same, ospreys, cormorants, darters, fishing eagles, mergansers, fish owls and white-tailed sea eagles hunt medium-to-large fish, and gulls, terns and kingfishers take smaller ones. Besides fish, the rivers, marshes and lakes support a wide array of crustaceans, mollusks, frogs, tadpoles, worms, aquatic insects and so on, which are preyed upon by herons and storks (both also take fish), bitterns, waders and crakes. Moorhens, cranes, ducks and geese feed on the same things, but are also vegetarians to a greater or lesser extent, eating roots, tubers and seeds of aquatic plants. The greylag and barheaded geese, teals, pintails, spotbills and garganey are largely plant-feeders and partial to cultivated fields, as are the common and demoiselle cranes. On the other hand, the hand goldeneye and the tufted duck are believed to be more depended on animal food.

Birds of prey (including owls) hunt small mammals, birds, eggs and nestling, besides reptiles and insects. Vultures maintain sanitation in nature by scavenging. Green pigeons are fruit-eaters, and their smaller relatives, the doves, are grain and seed-eaters. Parakeets, which are a bit of both, do much damage to crops and orchards. Sparrows, munias, buntings and weavers feed on grass seeds, and sunbirds live on the nectar of flowers.

Hornbills, barbets, orioles, mynas and bulbuls subsist mainly on fruit, but supplement their diet with insects. The reverse may be true for many of the remaining birds. Insects are hawked in the air by bee-eaters, swifts, swallows, martins and drongos; woodpeckers and nuthatches search for them on tree trunks, and wall creepers on vertical cliffs.
Pittas scan through leaf litter, forktails hunt forest streams, and wagtails prey upon insects along the stream and river beds. Bush chats, babblers, shrikes and prinias control insects in the grasslands, together with the rare rubythroat and the bluethroat, prefer to stay on the ground. Others such as minivets and allies, flycatchers, leaf warblers and cuckoos hunt insects in the forest canopies.

Red-billed blue magpies may be seen at the tiger kills early in the mornings, and the dark kite and the house sparrow live alongside man. Elsewhere flowerpeckers are closely associated with mistletoe fruit. Jungle mynas ride on rhinos, and often flocks of them betray the presence of the pachyderms in tall grass. The mynas benefit by feeding on insects that fly off the vegetation as the clumsy giants crash through it. Similarly, egrets and pied mynas accompany grazing herds of cows and buffalo. While some birds are highly-specialized feeders, others tend to be omnivorous in varying degrees.

At the apex of the avian food chain are the birds of prey, and apart from the vultures, which congregate in large numbers at a carcass, they are usually seen singly or in pairs. The ways in which evolution has adapted these birds of prey for a life of hunting or scavenging can be seen in the make up of their wings, tails, feet, beaks and eves.

In over a hundred species of birds that are seen in Chitwan, the males differ from the females in appearance. Yet the differences, although pronounced in some, are only minor in others. As a general rule, males are more brilliantly colored and therefore more attractive: minivets, peafowl, junglefowl, parakeets, sunbirds, woodpeckers, green pigeons, most ducks and flycatchers - are all good examples. In the great majority of our birds, however, both sexes look alike.

Courtship display - an integral part of pair-formation - varies as widely as do the species themselves. From January to May the spectacular dance of the peacock is a common sight in Chitwan: the male raises his tail- feathers vertically into a huge fan, with the iridescent moons facing forward, and pivots back and forth in a graceful pavane. Scarcely less impressive are the displays of the egrets during the monsoon. These slender, longlegged white herons raise and lower their feathers, forming white sprays round their crests and bodies, and thereby making themselves still more striking. Another of the great sights of spring is the flight display of the crested serpent eagle. Twisting and turning and rolling in the air, each pair performs thrilling aerobatics.

By late April most of our winter birds have gone, while others have arrived for nesting. As the breeding season begins, songsters fill the air with lovely melodies, and after dark the nightjars, owls and cuckoos sing all night long. In short, the males are competing with other males for mates, but that is not the whole story. The female painted snipe and common bustard-quail are larger and slightly brighter-colored than the male.

Most of our wintering ducks and waders are Trans-himalayan migrants, their breeding grounds extending as far north as Siberia and the Arctic circle. Some annual migrants travel vast distances. Yet many birds are merely regional migrants, and do not travel long distances. The paradise flycatchers and the black-naped monarch flycatcher arrive for breeding in summer from within the Indian subcontinent. Wintering leafwarblers and flycatchers such as orange-gorgetted, rufous- breasted, rusty-breasted, little pied and slaty blue, are said to breed higher up in the Himalayas, and are therefore latitudinal migrants. Still other birds use Chitwan only for a brief stopover on their way to or from their breeding grounds. These include the demoiselle crane, sooty flycatcher, curlew and spot winged stare.