Monsoon delay hits butterfly migration

CHENNAI: The delay in the onset of the northeast monsoon has hit the migration of butterflies in the city, leading to poor sightings and leaving conservationists disappointed.



While a lot more study needs to be taken up to establish the causes that affect migration, S R K Ramaswamy, a conservationist, said observations by teams of watchers team revealed that the setting in of the monsoon generally triggered the regular migration out of the city, in October, while the reverse instance occurred in April.



Vikas Madhav, a birder and a keen butterfly watcher, said that despite some good sightings in the suburbs this season, the ‘flying out’ had not taken off as rapidly as it did last year. Nageswara Rao Park in Mylapore, Guindy National Park, IIT-M, the stretch of the Chennai-Bengaluru national highway from the city’s outskirts to Sriperumbudur, Nanmangalam and Vandalur zoo were some of the popular ‘sighting spots’, he said adding that rain, which pushes butterflies to migrate and pollinate plants helping them reproduce, was the main trigger for the start of the annual phenomenon.

The large numbers of non-nymphalid species such as emigrants and lion blues recorded last year have almost been absent this time, said P Homeland, an avid watcher.

The blue tiger variety, one of the most commonly seen each July, has been virtually non-existent.

The authorities concerned have been doing their bit to ensure exclusive zones for butterlies. The park created at the Vandalur zoo a few years ago was almost completely damaged when Cyclone Vardah ravaged the city in December 2016 and is now being renovated in a phased manner.

About 2,000 saplings of flowering plants have been planted and the park has attracted nearly 30 species of butterflies, said a senior zoo official. Most of them are commonly found ones. The zoo managers are planting both host and nectar plants to attract butterflies, he said.