Raptor Migration in Nepal

Juvenile Steppe Eagle (common migrant) 

Raptor Migration is more typical in the Northern than in the Southern Hemisphere, although part of the difference may simply result from under-reporting in the latter region.

Diurnal raptors constitute a diverse group of approximately 320 species of highly mobile land predators, specializing in different kinds of prey, and occurring in a range of habitats across six continents. One hundred and twenty-nine species, 40 percent of all diurnal raptors engage in periodic or seasonal movement biologist called migration. Although several species (22) are complete migrants (i.e., species in which 90 percent or more of the individuals move on a seasonal basis), most migrating raptors (107) are partial migrants (i.e., species in which less than 90 percent of all individuals move on a seasonal basis, while others remain sedentary). The remaining species (77) of migrants engage in seasonal movements of a more irruptive and local nature, for which movements are associated with less predictable environmental fluctuations.

As a group, raptors tend to be relatively large, lightly wing-loaded birds, capable of extended soaring flight (Kerlinger 1989). Many species engage in considerable slope and thermal soaring while on migration (Brown and Amadon 1968). Most, if not all, raptors migrate during the day, especially during periods of favorable weather. Most raptors avoid lengthy water crossings (Brown and Amadon 1968, Kerlinger 1989, Bildstein 2006). Although a few raptors undertake considerable east-west movements, most raptor migration is largely north-south (Kerlinger 1989), with birds moving between high latitude breeding areas and low latitude non-breeding grounds (Bildstein 2006).

Raptors frequently aggregate along established corridors while migrating, and concentrations of tens of thousands of birds regularly and predictably occur at certain geographic features, especially mountain ridges and passes, narrow coastal plains, isthmuses, and peninsulas (Haugh 1972). It is believed that raptors converge along leading lines (sensu Geyr von Schweppenburg 1963: 192) because of (1) favorable conditions there, (2) inappropriate habitats in adjacent areas, (3) landscape features that serve as orientation aids, or (4) combinations of the above (Broun 1948, Williamson 1962, Mueller and Berger 1967, Brett 1991, Bildstein 2006).


In Nepal there are two globally significant raptor migration corridors;


1. Thoolakharka (Khare of Kande):



View of Annapurna Mountain range from Thoolakharka

Thoolakharka is a mountaintop watch site, geographically located in 28°17'19''N, 083°49'41''E, at the

Mountain Hawk Eagle (resident) 

elevation of 1764 m . This watch site is the representative of raptor migration in the region and appears to be a major corridor for migrating Steppe eagles (Aquila nipalensis) and other raptors, including endangered, vulnerable and near threatened species. It is situated on the trekking trail that connects the small town of Kande along the Pokhara-Baglung highway to the south and Annapurna Base Camp (ABC) to the North, approximately 35 km northwest of Pokhara in the foothills of Himalayan Mountains of central Nepal and South of Annapurna Himalaya range. Thoolakharka has a 360° view of the surrounding countryside, including the Hyangja valley to the east and the Marsikhola valley to the south. Agricultural lowlands surround the site, and oak-rhododendron forest occurs at higher elevations. Approximately 14,000 migratory raptors of 36 species including Amur falcon (Falco amurensis), Lesser kestrel (Falco naumanni) globally threatened Egyptian Vulture (Neophron percnopterus), and Saker falcon (Falco cherrug) use this corridor during autumn migration . The above information comes from two full season counts in autumn 2012 and 2013 (starting from 15 Sept through the first week of December). For detail please visit https://www.dropbox.com/s/dhplcklnou4rova/2013.FinalReport.Nepal4.pdf from where you can freely download our 2013 final report.

2. Kaligandaki valley: Kaligandaki river valley (NP - 02), appears to be major corridor for the migrant raptors; located between 29°10' to 28°20' N, to 83°30' to 84°00' E and in between the altitude of 800 – 4500 m. It is identified as internationally important raptor migration sites and representative of the Himalayan region (Zalles and Bildstein 2000). About 100 km long river valleys watch site descending from the Tibetan Plateau to the midland of West Central Nepal. The north end of the valley narrows at Jomsoms at 2800 m before continuing south at 2600 m between two mountain peaks Dhaulagiri and Annapurna that create the deepest gorge in the world. About 8,000 individuals of about 20 species of raptors have been seen in one season. However, eighteen species appear to be regular migrants at the site. The site is used by migrating Demoiselle crane (Grus virgo), (> 63,000 in 1978) and Common crane (Grus grus) (Thiollay 1979). Threatened migrants includes Heliaeetus leucoryphus, Circus macrourus, Aquila heliaca and Falco naumanni.