Overview
The Himalayan Range serves as one of the world’s most important migratory corridors for birds of prey, guiding more than 30 raptor species from the Tibetan Plateau and northern Asia - including Mongolia, China, and eastern Russia – to their wintering grounds across the Indian subcontinent, the Middle East, and Africa. Among the most numerous migrants are the Steppe Eagle (Aquila nipalensis) – an Endangered species and the Himalayan Vulture (Gyps himalayensis) – a Near Threatened species.
To monitor these migrants, the Himalayan Raptors conducts systematic autumn counts at Thoolakharka, a globally significant migratory bottleneck in central-west Nepal. Situated along a prominent ridge, Thoolakharka is unique in global ornithology as the only known watchsite where raptors migrate predominantly from east to west, offering an unparalleled opportunity to study long-distance avian movements.
The data collected here play a vital role in tracking population trajectories within the Central Himalayan Flyway and assessing the effectiveness of global conservation efforts.
The Conservation Crisis
The Steppe Eagle: A Species in Decline
In Nepal, this decline is starkly visible: historical counts from the 1980s estimated approximately 45,000 individuals, but that number has plummeted to roughly 6,000 birds in recent years—representing a catastrophic 85% loss over four decades. Throughout their flyways, these apex predators face compounding anthropogenic threats, including:
- Infrastructure Hazards: Rapidly expanding networks of poorly insulated power distribution lines (causing high electrocution risk) and collisions with newly developed wind turbines.
- Environmental Pressures: Secondary poisoning, habitat degradation, and local persecution.
Why Thoolakharka?
The Foothill Funnel Effect
Monitoring raptor populations across their vast breeding ranges in central and north Asia, including Kazakhstan, Mongolia, and the Altai Mountains, is logistically difficult. Migratory bottlenecks like Thoolakharka concentrate thousands of birds into a narrow flight corridor, making population monitoring far more effective.
Furthermore, Thoolakharka is subject to a unique meteorological phenomenon: when heavy autumn clouds obscure the high mountain passes of the Annapurna Range (located just 20 km north), migrating raptors—particularly Steppe Eagles—are forced to shift their flight path southward into the lower valleys. This meteorological "funnel effect" brings birds directly over the watchsite, often at eye level and within 20–80 meters of the observer at the watch hill, allowing researchers to achieve unparalleled accuracy in counting and ageing.
Thoolakharka is also globally significant because it supports the highest known concentration of the eastern subspecies, Aquila nipalensis nipalensis, making it an irreplaceable monitoring site.
What We Do?
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Population Monitoring and Migration Phenology
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Flyway Diversity Monitoring
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Community Outreach and Citizen Science
Historical Context and Long-Term Trends
Long-term data highlights why continuing this multi-year dataset is so vital:
- Steppe Eagles: Migration count at Thoolakharka shows a sharp decline from approximately 8,500 individuals in 2012 to just 3,900 in 2020. Encouragingly, the latest 2024 count documented a notable rebound to 6,603 individuals. Maintaining the 2026 full-season count is essential to determine whether this increase reflects genuine population recovery or merely a short-term, weather-driven fluctuation.
- Himalayan Vultures: Unlike Steppe Eagles, migration metrics for this species have remained stable or shown modest increases since 2012, serving as an excellent control baseline for evaluating different raptor feeding guilds.
Support Our Flight
By monitoring the majestic raptors of the Central Himalayan Flyway, the Himalayan Raptors generates the knowledge needed to protect these species across international borders. Follow our journey during the upcoming 2026 autumn migration season and help us safeguard one of the world’s most extraordinary natural spectacles.
