Summer visitors flying in without passports
A total of 887 birds have been recorded from Nepal so far. The latest find, the Sooty Tern was recorded from KoshipTappu in mid-June 2017. Discovered by Koshi based field ornithologistAnishTimsina, the bird, however, was an unexpected visitor for this country.
“This bird was supposed to be living around the ocean coast but by rare chance came too far inland to Koshi,” says Dr. Hem SagarBaral, noted bird scientist of Nepal.
But there are dozens of other birds that are expected as regular visitors during summer. The distinct calls and songs produced by these birds these days make us aware that they are around.
Nepali people are quite familiar with the seasonal song of the KafalPakyochara (Indian Cuckoo) which can be heard in the hills at this time of the year. We in Nepal translate the song as saying that the well-known berry with the local name of Kafal is ripe. Interestingly the bird sings it when Kafal is actually ripe in the hills and mountains and ready to be picked.
There are also other summer visitors that attract our attention with their call and colours. The Red-winged crested cuckoo is famed for its beautiful look that contrasts with the green background of the trees. Equally eye catching is the Asian Emerald Cuckoo that matches with the greenish sparkle of the precious stone emerald. This insect eater inhabits mainly in dense evergreen forests.
Other summer visitors of cuckoo variety that can be identified with their distinct seasonal call are the Eurasian cuckoo and Asian Koel followed by the Himalayan cuckoo and grey-bellied cuckoo.
“Around 50 species of birds come to Nepal as summer visitors and most of them belong to the cuckoo family,” says Dr.Baral. They come from South India, Sri Lanka, Thailand, Malaysia, Myanmar and Indonesia. The Jure Koili (Pied cuckoo) is even suspected to have come from as far away as Africa.
Why do they migrate to Nepal in summer? “They come from the tropical areas in the south and the principal purpose is breeding,” says Dr.Baral.
But the fast flying swifts such as the White-throated needle-tailed swift are said to be currently in Nepal on their longer path of migration towards Mongolia and Central Asia.
Four species of bee-eaters are found in Nepal of which two are purely summer visitors. Two birds of pitta family, namely the Indian pitta and hooded pitta also fall in the list of summer visitors to Nepal.
The large-billed leaf warbler locally known as Fisto come from South India and breeds in the high altitude of up to 4,000 metres. “This bird with 13-cm body length is probably the smallest summer visitor to Nepal,” says Dr.Baral.
Yet another visitor coming from South India is the Asian paradise flycatcher locally known as Swargachari. The long-tailed bird is among its peers of the family including the Dark-sided flycatcher, rusty-tailed flycatcher and ferruginous flycatcher. Similarly the pied-thrush is a summer visitor from Sri Lanka.
One of the most startling behaviour of the summer visitors of the cuckoo variety is that they do not make their own nests and cleverly lay their eggs in the nest of other birds instead. The host birds are fooled that they are hatching their own eggs and raising the cuckoo chicks. Witty birds such as crow and drongo are easily fooled by these crafty intruders.
The Asian Koel is notorious for laying its egg in the nest of an incubating crow and tricking the host to provide full service in chick raising. Usually, a male Koel plays its part to approach and disturb the crow, forcing it to leave its nest in an retaliatory chase. Meanwhile, the female Koel is hiding nearby and waiting for the right moment. When the crow flies out of the nest angrily chasing the intruder, the female swoops in the nest, removes the crow egg and lays its own. As the egg of the intruder is almost similar in size and colour, the crow has least suspicion about the tricky replacement. She faithfully incubates the intruder’s egg, hatches it and feeds the chick until full growth.
“It is really interesting how the female Koel manages to lay egg within the short, stolen moment,” says Dr.Baral.
Crow is not only the host bird that is tricked by cuckoos to incubate and hatch their eggs and raise their chicks. Indian cuckoo lays its egg in the nest of Drongo (Chibechara) while the Eurasian cuckoo tricks bulbul for the chick rearing service.
A total of 19 species of cuckoo birds are found in Nepal. But only four of them build their own nests and hatch their chicks. Fifteen others play the tricky game of laying eggs in somebody else’s nests.
The arrival of summer visitors starts in February and these birds stay in Nepal till October. At the end of their migratory stay here, all of them including the young ones, invariably return to the places from where they came.
“Even if the young ones do not have their parents to accompany, they will return to their homeland on their own. They possess this unique kind of genetic instinct,” says Dr.Baral. Even scientists are often baffled by the extraordinary navigational capacity of the migratory birds.
Unlike the winter migrants, the summer visitors mainly live and forage in forest based habitats. But the altitudes vary. They inhabit in the jungles of the Terai, mid-hills and the mountains. Nepal’s altitudinal, climatic and forest diversity has helped to attract wider range of summer visitors. Things need to be confirmed through research but the adverse changes in local forest habitat and the population of host birds can affect the arrival trend of summer visitors, says Dr.Baral.
“In the past, I used to frequently hear the call of KafalPakyochara in Kathmandu at this time of the year. But the sound is rare in recent years,” he adds.
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