Namjaa and Onon are the names which have been given to two Common Cuckoos. The two birds were fitted with transmitters by scientists in northern Mongolia in June – they have now reached India after flying for thousands of miles, as part of one of the animal kingdom’s most fascinating journeys – one that researchers are only now beginning to understand in its entirety.

Scientists said that the birds are expected to stay in India till the end of October before they embark on the final lap of their migration and cross the Arabian Sea to reach Southeast Africa, where they will spend the winter.

“Both Namjaa and Onon are now in Madhya Pradesh. On September 7, Namjaa was traced around 50km south of the town of Chattarpur. The habitat looked like a small range of hills. Onon was traced around 18 km South-east of Gwalior,” said Terry Townshend, a British conservationist who launched Birding Beijing in 2010.

Between June 4 and 8, five cuckoos – one Oriental Cuckoo and four Common Cuckoos – were fitted with transmitters around the Khurkh Bird Banding Centre in northern Mongolia. The birds were named by local schools. While Namjaa is the name of a storyteller in Mongolian folklore, Onon is the name of an important river in Mongolia.

The project is a collaboration between the Wildlife Science and Conservation Centre in Mongolia, the British Trust for Ornithology and Birding Beijing, and supported by the Oriental Bird Club.

The other three birds have been traced in other countries. Nomad, an Oriental Cuckoo, was tracked to inner-Mongolia on Sunday after crossing the Gobi Desert, 800-1600 km wide in an overnight flight. It is the first Oriental Cuckoo to be tracked. Scientists from Birding Beijing carried out a similar exercise in 2016.