Prey Species in the Diet of the Amur Falcon (Falco amurensis) During Autumn Passage Stopover in Northeast India

We recorded the diet of Amur Falcons (Falco amurensis) during their autumn passage at stopover sites across in Northeast India. We collected and examined 1200 pellets to identify prey remains in the diet of Amur Falcons from three major stopover sites in Nagaland State in the years 2017 and 2018. Additionally, in 2019, we examined 200 pellets each at two other sites in the neighboring states of Assam and Manipur. We only recorded insect prey belonging to five taxonomic orders: Orthoptera, Isoptera, Hemiptera, Coleoptera, and Hymenoptera, with Isoptera being dominant in the diet of Amur Falcons. The frequency of occurrence of Isoptera (termites) was the highest (87%) across years and across all stopover sites in Nagaland; diets were similar at the two other sites in Assam and Manipur. We identified the species of termites in the diet of Amur Falcons as Odontotermes feae and O. horni, the mass emergence of which coincided with the falcons’ arrival in the region. We further estimated that 1,000,000 Amur Falcons stopping over for an average of 15 d in the region consumed approximately 67–134 metric tons of alates (approximately 1 to 2 billion individual alates). We concluded that Amur Falcons stop over in Northeast India primarily to refuel. Our study highlights the importance of availability of abundant termite prey for the success of Amur Falcons’ onward migration, which includes oceanic crossings en route to Africa.