Internal bird migration begins in Nepal

By Baburam Karki,Baraha Kshetra, Oct. 16: As autumn begins and the rainy season comes to a close, birds have started their internal migration in Nepal. They have now started moving towards the Koshi Tappu Wildlife Reserve (KTWR) and surrounding areas.

The migration is triggered by the cold temperatures in the hilly districts, prompting the birds to move to the lowland areas.

Noted ornithologist Dr. Hem Sagar Baral explained that birds from hilly regions, at elevations between 2,000 to 3,000 metres, are descending to the Tarai to escape the cold. Species such as Bhadrai (Lesser grey shrike), Fisto (Common tailorbird), Chuiya (Himalayan cutia) and Arjunak (Flycatcher) are migrating from the hills to areas around KTWR (often referred to as the bird capital of the country).

Birds are being sighted in the plains, jungles, and wetlands of districts like Sunsari, Morang, Jhapa, Saptari, Udayapur and Siraha. 

According to Baral, after nesting in the hills, the birds move to the Tarai to avoid the winter chill. Migratory birds from the hills start arriving in the Tarai by mid-October.

The birds play a crucial role in controlling pests by feeding on insects that affect winter crops, benefiting local farmers. Experts point out that in recent years, the reduction in migratory bird numbers has led to an increase in pest infestations in crops. Bird migration has been declining in recent years due to various reasons.

The migratory birds that arrive in October typically return to the hills when temperatures rise in the Tarai. Nature guide Anish Timsina said that a single Fisto bird can consume 300 to 500 insects daily. The Arjunak species feeds on ground insects, while the Chuiya species hunts for insects in grassy areas of the jungle. The Bhadrai species mainly feeds on pests found in fields and farms.

Agriculture technician Nir Bahadur Rai from Baraha Kshetra Municipality said that since fewer birds are seen in the fields now, pest infestations in crops have been increasing.

The decline in bird populations in recent years is believed to be due to pesticides used to control insects, which weaken the reproductive capabilities of insect-eating birds. Dr. Baral added that these migratory birds, which come to the Tarai to escape the cold, begin returning to the eastern hilly regions by late February or early March, as temperatures rise in the plains.