Tracking the Rain birds, a tech challenge

For the first time in India, the Pied Cuckoos (Jacobin Cuckoo, also called the rain bird) have been satellite-tagged to track their migration from the Himalayan foothills to Africa and back. Two of these birds were tagged with solar-powered transmitters.

The migration study is a project of the Indian Institute of Remote Sensing (IIRS) in collaboration with the Dehradun-based Wildlife Institute of India (WII). The Pied Cuckoo has been closely linked to the onset of southwest monsoon.

The two birds, named Megh and Chatak, were captured and tagged on July 12 and 14. “The cuckoos did arrive with the monsoon. Only after a month of trial did we manage to catch the two using mist nets,” informed Dr Suresh Kumar, a scientist attached to the WII.

The cuckoos were captured in the agricultural fields near WII’s Dehradun campus and deployed with a tag weighing 2g. The Uttarakhand Forest Department had approved the process.

“This is the first such attempt using high-end satellite technology to track the Pied Cuckoo.”

“So far we have had no direct evidence of the route these birds take. Last year, we banded a Pied Cuckoo on the outskirts of Dehradun to check whether it would return to the same site the following year. Sure enough, the bird returned this summer,” Dr Kumar said.

Tracking the long-distance migration of the Pied Cuckoos (Rain birds) from the Himalayan foothills to Africa and back has been a technological challenge, given the cuckoo’s low body weight. But a solar-powered transmitter, weighing just two grams made it easier for the Wildlife Institute of India, Dehradun.

Adult cuckoos weigh between 65 to 75 grams. “So, any tracking device to be put on them needs to be really very small or the thumb rule is it has to be less than 3% of the body weight. Thankfully the transmitter from Microwave Telemetry Inc. USA was available, though only on a limited order basis,” noted Dr Suresh Kumar from WII.

Popularly called the Rain bird, the Pied Cuckoo is a summer breeding visitor to Northern India, originating from Southern Africa. In North Indian folklore, the bird has been known as the “Chatak” that quenches its thirst only with raindrops.

Once the birds were satellite-tagged, scientists had to track them. “Signals from Megh and Chatak have been coming in regularly, and the birds are moving around the site they were captured. They are now expected to stay in the Dehradun valley till the end of the monsoon season,” Dr Kumar said.

The birds will start their southbound migration in late September. “I am hopeful that the tagged cuckoos will give us lots of data and improve our understanding of these amazing long-distance travellers.”

Here’s what is next: “An online web-based geospatial dashboard will be developed now for near-real-time monitoring of trends and patterns in movement of Pied Cuckoo i.e., development of a location analytical tool with an API for interoperability and to perform geospatial modeling,” explained Dr. Sameer Saran, Indian Institute of Remote Sensing.