It wasn’t yet 6 in the morning, but the eclectic bunch of people gathered outside the Okhla Bird Sanctuary was already sweltering. Large cameras, with larger lenses, hung around their neck or shoulder. High-tension wires ran overhead, giving out strangely a waterfall-like sound, as the group prepped for Delhi’s first-ever summer bird count on Saturday.

Kanwar B Singh, a retired navy officer and multinational executive, led the small group into the 4-sq-km sanctuary on the maiden attempt to count Delhi’s resident birds. “The endemic count will help us understand their distribution [of birds] in our region,” the ornithology enthusiast announced, pointing to green pigeons through a camera. “It will also help us gain information about the locations of breeding birds.”

All that it certainly did.

The bird count was conducted on May 14, on the occasion of the Endemic Bird Day and Global Big Day. Eight birders spread across the city in the oppressive heat in small groups early in the morning to watch the city’s feathered natives. And once the blistering work was done, the count was 188 species – 152 of them residents and 36 lingering stray migrants.

Birding events and bird counts are traditionally held in winters, when there are more bird species and the weather is pleasant enough to spend a whole day outdoors. This is particularly true for a tropical country like India. During past winter-time excursions, 400 species of birds had been recorded in the National Capital Region, including resident birds that breed here, local migrants, summer breeding visitors as well as winter migrants.

This, however, meant there was no data on endemic birds that breed during summers. As Singh put it, “In summers, even though the species count is lower... a bird count can generate important data on the diversity of our resident birds, important local habitats... and the state of these habitats.”

Singh’s other hope was that the summer bird watch would help popularise the diversity of the region’s birdlife among a bigger section of the population.

At Okhla Sanctuary in south Delhi, Soni, an eight-year-old Labrador, hung around the birders with her trainer. A veteran of such walks, she didn’t bark or disturb the birds – much like the birders who took extra care to create no noise and do no harm to the environment.

The group quietly watched a colourful kingfisher perched atop a branch. Elsewhere, local residents – the yellow-bellied prinia, street weaver birds and green pigeons – were nesting. One birder spotted a red headed bunting, a rare migrant bird passing through Delhi. The outbreak of excitement at the knowledge made it clear that this was the highlight of the day.

Ashwini Vaidya, a post-doctoral fellow at the Indian Institute of Technology-Delhi, was elated to spend time at the Okhla Sanctuary. Though a birder for the past 10 years, it was her first time here. “We spotted winter migrants which still hadn’t returned – three greylag geese and a perigrine falcon,” the 33-year-old said, with evident excitement.

Her husband, Samar Husain, 33, a faculty member at IIT-Delhi, was happy but also miffed.

He felt strongly about the central government’s decision last year to reduce the area of the eco-sensitive zone around the Okhla Sanctuary. Traditionally, the National Green Tribunal had restrained development of any infrastructure within a 10-km radius from the sanctuary’s boundary. But all that went out the window when the sanctuary’s eco-sensitive zone was cut down to 100 metres.

“That’s a lot of space being taken away from the birds,” Husain lamented.

Here are some of the attractive birds spotted on Endemic Bird Day: