As loudspeakers blare out the arrival of buses and vehicles honk their annoyance at the stop-and-go traffic, the East Fort area possibly records the worst levels of noise-and-air pollution in the city. And finding a bubble of silence in this urban locale took seasoned bird-watchers based in the city by surprise.

They belonged to the group Warblers and Waders, a collective of naturalists who are in the process of compiling a list of bird and butterfly species found inside Government Central High School, Attakulangara.

A few hours of scouring the grounds for winged visitors early Sunday morning and the participants already had a long list of species, some even deemed rare, considering that they were found in one of the most congested regions of the city. They identified 30 species of birds and 22 species of butterflies inside the campus, C. Sushanth, programme coordinator, said.

Among the birds sighted were three migratory ones – the Golden Oriole, Blyth’s Reed Warbler, and Brown Shrike. Other sightings that Mr. Sushanth described as significant were that of the White-breasted Waterhen, Night Heron, Brahminy Kite, Cattle Egret, Little Cormorant, Coppersmith Barbet, and Shikra.

Mr. Sushanth succeeded in getting photographs of a Black Drongo nesting. They spotted the Green Barbet and Jungle Myna nesting as well.

Among the butterfly species, the team members recorded the presence of the Indian Skipper, Common Jay, Tailed Jay, Mottled Emigrant, Plain Tiger, Striped Tiger, Blue Tiger, and Common Mormon. A migratory damselfly called the Wandering Glider also made an appearance, much to the joy of the participants. The Coromandel Marsh Dart, Orange-tailed Marsh Dart, Ground Skimmer, and Common Picturewing were the other dragonflies and damselflies documented.

“We had previously conducted surveys inside the city limits, such as at the Museum and Golf Links premises. Even so, we were very surprised that this limited space is home to species that you would normally find in a rural, more natural environment,” Mr. Sushanth said. The wide, rich canopy provided by the trees on the campus protected this rich ecosystem, the team observed.

Mr. Sushanth said since April was not the season when most migratory birds came to nest, there were fewer birds than there would have been later in the year. In fact, the group was considering supplementing their list of species towards the latter half of the year – when at least 10 additional bird species were expected to flit in.

The members of Warblers and Waders were supported by the environmental group Tree Walk Thiruvananthapuram.