TN’s biomes aflutter with butterfly migration

housands of butterflies took to the skies a few weeks ago, in Aanamalais and Coimbatore, migrating from the Western Ghats to the Eastern Ghats, much to the delight of nature lovers and researchers. Every year, butterflies migrate across Tamil Nadu, moving from the Nilgris to Javvadu Hills and Thirumala Hills before arriving at Satyamangalam Reserve Forest, which is the meeting point of the Western and Eastern Ghats. However, in 2016 and 2017 there was hardly any migration, due to poor rainfall and with the State under pressure for water until the onset of the southwest monsoon, there were fears that the butterflies may not migrate.

In Chennai, too, the butterflies are in plain sight, after the rain, breaking a 190-day spell of dry weather. Last Sunday, several walkers and golfers were excited to spot a swarm of butterflies at a mud track on the golf course in Guindy, where racehorses are routinely taken for a walk. The butterflies were engaged in mud puddling, a process of sucking up nutrients from the rain and urine (from horses) soaked earth.

“Butterflies are bioindicators and the sight of them in good numbers everywhere is an indication that the population is healthy,” said Theivaprakasam Hari, a researcher at Nature and Butterfly Society (NBS). “Butterflies (only some species) migrate due to various reasons but is primarily triggered by climatic phenomena and in association with depletion of its host plants,” he added. Unaffected by obstacles on the way, butterflies in Tamil Nadu follow two major migratory patterns. From April end, they move from the Western Ghats, flying from places like Coimbatore and Tirunelveli, to Javvadu Hills, Shevaroy Hills, etc. in the Eastern Ghats. Towards the fag end of September, they fly back to the Western Ghats. “Concerning Chennai, the migrating butterflies cross towards Villupuram and beyond in July and they fly back over Chennai in the first week of September en route the Eastern Ghats. Between September 24 and 26, the mass migration towards the Western Ghats begins,” said Hari. The migration pattern not only helps them avoid monsoon fury but also enables them to hibernate before they commence laying eggs. Experts say that wherever the butterflies find host plants, they lay eggs and whenever conditions are conducive, the eggs will hatch. The process of mud puddling is also common ahead of the breeding season. “Male butterflies suck up the minerals from the earth and then transfer them to female butterflies, ensuring the larvae are healthy when the eggs hatch,” said R Bhanumathi, naturalist and author.

Given that the lifespan of a butterfly is very short, the same butterfly may or may not make the return journey during migration. Fresh eggs may hatch and new caterpillars turn into butterflies and join the migrants as newbies. “Tamil Nadu has 324 varieties of butterflies and we have validated (record of sightings, etc) 311 in the last six years,” said Hari, who, along with other NGOs, recommended certain butterflies to the Forest Department when it was in the process of selecting the State butterfly. NBS had recommended the Common Banded Peacock (Papilio crino) found in 23 districts of the Sate, but the Tamil Yeoman, Cirrochroa thais (Maravan in Tamil), found in the Western Ghats was declared the State butterfly by the government, in a GO passed on June 28.

A lot of consultation went into naming the State butterfly. Over a dozen parametres were taken into consideration, said Sanjay Kumar Srivastava, Chief Wildlife Warden, Tamil Nadu. “Tamil Maravan was chosen because it is unique in many ways. We are identifying with the Tamil culture. The Western Ghats is a biodiversity hotspot and at any given time you can find 30-35 types of butterflies there. When you declare a species representing the State, a gamut of other species also falls within it and the steps and measures taken to conserve such species will benefit the entire area,” he said. Pointing out that the declaration of State animal, tree, bird and fruit comes from a larger conservation perspective, and enables further scientific study, Srivastava said,” People are familiar with tiger and elephant conservation measures. Not many realise the importance of the butterflies. They can survive only if the topography, plant and animal population and moisture content of their habitat remain healthy. We have a butterfly park in Arignar Anna Zoological Park and a larger one in Tiruchy. If any species depletion is witnessed, we can step in, but as butterflies have a very short lifespan, we should do everything we can to protect them.” When asked about threat to butterflies, he recalls the cases of illegal trade in butterflies in the North East decades ago. “Butterflies, too, are susceptible to smuggling. There is a demand for it for various reasons, including textile design. People need to be aware of the importance of the butterfly. Its presence or absenceis an indicator of climate change,” he said.

Hari of NBS echoes the same sentiment and added that butterflies were winging their way on earth much before man came to inhabit it. “Tamil Maravan got its name from the fact that these butterflies behave like patrolman – they chase away any other butterfly from encroaching upon their space. They are brave in a way, doing yeomen service. It is endemic to the Western Ghats and some parts of Sri Lanka. Naming it the State butterfly is apt as we need to preserve what is native to our State,” he added. According to him, the Forest Department consulted five NGOs and butterfly experts, after which it formed a 10-member committee to identify the State butterfly. Karnataka, Kerala, Goa and Uttarakhand had already named their State butterflies by then. The Forest Department was keen to name one that had certain unique qualities “and Tamil Maravan ticked all those boxes,” added Hari. He also cautioned that the butterfly population could face a crisis if there is habitat threat due to deforestation. “Butterflies are native species, which means they cannot thrive if alien plants are introduced. Also, the use of chemical pesticides will result in loss of larva or worse, result in deformed butterflies. They need to be protected,” he added.

According to S Balaji, former Chief Conservator of Forests, Tamil Nadu, the State has been periodically naming its State flower, tree, animal, etc. “The Description Gloriosa lily was declared the State flower decades ago. Over the years, the government has declared the palm as the State tree, jackfruit as the State fruit, the Nilgiri tahr as the State animal and the emerald dove as State bird. The Tamil Yeoman is the latest addition. The aim is to create more awareness among the common man about the conservation of larger biodiversity of the State. In ancient times, poets used to sing their paeans,” he said.

Interestingly, the emerald dove does not feature in any literature, although the common dove and pigeon have a marked their presence, said T Parameshwari, a poet and a teacher of Tamil. “The palm tree features in Needhi Venba and also in Sekkiizhar’s Naladiyar. There are a number of proverbs based on palm trees, many of which are still in use. For example, “Even if one drinks milk standing under a palm tree, people will say he is drinking toddy.” The palm leaf was a major communication tool and news in the Sangam era and messages were exchanged on palm leaves, pointed out Parameshwari. She also added that in Sangam literature a woman’s hand was often compared to Gloriosa lily, as a mark of beauty. Tara Gandhi, ornithologist and nature writer, said the emerald dove resides in hilly areas, “But when you think of Tamil Nadu, you immediately recall a vast coastline. I have seen Gloriosa lily in the Theosophical Society and a few other places, but it is not very uncommon,” she added. The palm tree is ecologically sensitive, too, and it is a nesting place for certain birds like swifts and swallows. It’s important we conserve this species of tree,” said Gandhi. The goat family, to which the Nilgiri tahr belongs, finds copious mention in literary works such as Natrinai, Ainkurunanooru, Pathitrupatthu, Paripadal, etc., said Parameshwari. “To that extent, all these State symbols are truly Tamil and endemic to the region,” she added.