How do Amur falcons fuel their 2,000-mile flights?

A single million-strong population of Amur falcons (Falco amurensis) can consume up to two billion termites in just over two weeks, according to a new study. 

These large numbers highlight the vital role that Northeast India plays as a stopover site for these falcons during their migration. 

The region allows the birds to prepare for their non-stop flight across the Arabian Sea, a journey that gives the Amur falcon the distinction of making the longest known overwater flight of any raptor.

Fall migration of Amur falcons

Amur falcons are small birds of prey that migrate twice a year between northern Asia, where they breed, and southern Africa, where they spend the winter. Their autumn migration involves a 3,500 km (2,000 mile) journey across the Arabian Sea. 

To successfully complete this flight, the falcons must build up energy reserves by feeding on protein-rich food, and termites are their preferred choice. 

In the paper titled “Prey Species in the Diet of the Amur Falcon (Falco amurensis) During Autumn Passage Stopover in Northeast India,” lead author Amarjeet Kaur from the Wildlife Institute of India and her co-authors identify the region of Nagaland in Northeast India as a critical stopover for the falcons. 

As insect-eaters, the Amur falcons likely rely on termites to fuel their migration, making this area a priority for conservation.

Dominant prey for Amur falcons

To assess the role of insects in the falcons’ diet during migration, Kaur and her team analyzed more than 1,000 regurgitated pellets collected from beneath an Amur falcon roost in Nagaland in October and November of 2017 and 2018. 

These pellets, which contain undigested prey remains, showed a high concentration of body parts from two species of fungus-growing termites, Odontotermes feae and Odontotermes horni. Termites were the dominant prey for the falcons across both years and at all three roosting sites studied. 

The researchers also observed numerous Amur falcons feeding on termite swarms, providing further evidence that termites are a crucial food source. 

Termites offer easily digestible protein and are rich in fat, a fact well-known to local hunters who historically called Amur falcons “loi,” meaning “insect eater.” In the past, hunters would capture the falcons late in the season, when their consumption of termites had resulted in a rich layer of fat.

A symbol of conservation efforts 

Today, the local Naga communities have become active in protecting the falcons, moving away from hunting them during migration.

Senior author Suresh Kumar initially began this research to raise local awareness about the falcons, and now he says the birds have become a symbol for regional conservation efforts. 

“Local communities in Nagaland and neighboring States of Manipur and Assam have independently begun setting aside community lands for the protection of not only Amur falcons, but for all biodiversity in the area,” Kumar said.

“Given that Nagaland is predominantly governed by community-owned land, conservation actions are significantly shaped by local residents.”

Significance of the study

The study’s findings are significant because they underscore the importance of stopover sites in the yearly migration of the Amur falcon, especially the pre-Arabian Sea refueling site in Nagaland. 

Kaur and her team were surprised by the strong connection between the Amur falcons and termites, noting that “it appears that termites are the exclusive prey in this region, and the synchronization between termite emergence and the presence of Amur Falcons is remarkable.”

As long-distance migrators, the falcons are on a strict schedule and could be vulnerable to changes in the environment that disrupt this synchronization. 

Climate change has already affected other long-distance migrators, such as the Great Knots (Calidris tenuirostris) and Bar-tailed Godwits (Limosa lapponica). 

The study also emphasizes the role that insect-eating raptors like the Amur Falcon play in controlling insect populations, a fact supported by research on their wintering grounds in southern Africa.

Critical stopover sites 

Looking ahead, Kaur and her colleagues aim to identify specific features of Amur falcon stopover sites across Northeast India and use this data to develop a more comprehensive GIS-based model. They also plan to conduct a detailed study of termite populations at these sites.

“We need to determine if the termite swarming events are cyclic in nature and how they might be influenced by climatic factors, particularly monsoonal rains,” noted the researchers. 

Since the Amur Falcons may depend on just a few critical locations to gain the energy needed for their migration, understanding the connectivity between these sites is crucial. As the researchers conclude, “Amur falcon conservation requires a landscape-scale approach.”

The research is published in the Journal of Raptor Research.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–