Heronries are thriving in Thiruvananthapuram district, says a WWF survey

This year’s count recorded 27 active heronries and 742 nests belonging to seven different waterbird species. The count of 2021, conducted amid COVID-19 restrictions, recorded 233 nests of five species of waterbirds

A Little Egret found with its chicks during the annual heronry count conducted in Thiruvananthapuram

The annual heronry count jointly organised by WWF-India in association with the Forest department in Thiruvananthapuram district has recorded more heronries that in the past.

Heronry counts aims at counting ‘apparently occupied nests’ of herons, egrets, and other colonial waterbirds. This is regarded as an effective and accurate way to determine the breeding population of waterbirds in an area. Being one of the top predators in the aquatic food chain, monitoring their population can indicate the health of the aquatic ecosystem, freshwater as well as brackish water.

In Thiruvananthapuram, the annual enumeration is being conducted since 2016 by WWF-India’s Kerala State office along with various partners.

According to a press release, this year’s count recorded 27 active heronries while five were uninhabited. The volunteers found a total of 742 nests belonging to seven different waterbird species.

Bird species

The lion’s share of nests was of the Indian-pond Heron (430), followed by the Little Egret (101), Little Cormorant (60), Indian Cormorant (49), Blackcrowned Night Heron (21) and Oriental Darter (10). One nest of Purple Heron was also found at the Punchakkari paddy fields in Vellayani. While a majority were occupied nests, around 10% of nests were found to be abandoned. This apparently indicated the early breeding of certain species.

The predominant tree species hosting the heronries included teak, mango, copperpod tree, tamarind, rain tree, peepal, banyan tree. The heronry found in Vizhinjam housed the highest number of nests (173). Rajaji Nagar near Housing Board junction, Kumarichantha near Poonthura, and Kazhakuttom are some of the district’s other notable nesting areas.

No herony here

Six distinct locations, viz., Kumarapuram, Kannettumukku, Vellayani junction, Maruthoor, Panavila junction, and Kanyakulangara, had no heronry, which could indicate desertion or a different nesting season.

According to A.K. Sivakumar and Govind Girija, who coordinated the exercise, a majority of the nesting stages that the five teams observed were those of chicks and fledglings. Pointing out this indicated that this year’s nesting may have begun a little earlier, they hinted at the possibility of holding the programme in June next year.

The heronry count of 2021 that was conducted amid the COVID-19 induced restrictions recorded 233 nests that belonged to five species of waterbirds.

Many benefits

WWF-India State director Renjan Mathew Varghese said the annual programme held under the banner of People4Planet of WWF-India has multifold outcomes. “It helps to introduce many new people to the world of birds, birdwatching, and nature watch, and also provides a platform for budding birdwatchers to improve their skills in birding and contribute more to bird conservation in the long run. Heronries are usually atop huge trees and this exercise helps us to monitor the healthy tree cover of the city too,” he added.