<p>Bengaluru was witness to a <a href="https://www.deccanherald.com/tags/butterfly">butterfly</a> migration last week. Many social media users reported spotting swarms of butterflies moving past apartment buildings, houses, lakes and parks. </p>.<p>They seem to have disappeared after the rains over the last two days, butterfly conservationists say. </p>.<p>Experts note that it occurs before the southwest monsoon every year. “It is said that the butterflies move to the plains and the Eastern ghats to escape the rain, for survival and reproduction,” says Srivatsan R, an environmentalist. </p>.<p>However, there is barely any scientific explanation behind their migratory patterns and routes. Ecologists call for more scientific studies on the subject, to understand the phenomenon better. </p>.<p>“Perhaps the erratic rains affect their migratory patterns. And the species that migrate are likely adapted to certain conditions, unlike other species that don’t migrate. But sadly, there is no scientific evidence to back these claims. Hopefully someone will get inspired to study them,” says Seshadri K S, an ecologist and faculty, ATREE. Though it happens twice every year ‘like clockwork’, this year the migration caught the attention of Bengalureans because “the migrating swarm of butterflies does not enter the city — we do not know the reason for this”, says Rohit Girotra, founding member of Bengaluru Butterfly Club (BBC). The last time this happened was 5-6 years back. Girotra along with a group of others spent a few hours at the Savanadurga forest last week to watch the butterflies. “We spotted the Common Crow, Double Branded Crow, Blue Tiger and Dark Blue Tiger species,” he shares. </p>.<p>Karnataka has over 350 species of butterflies. Of these, mainly four species embark on this journey, he points out. “Most of these swarms were found to be ‘roosting’ in Savanadurga forest, Lalbagh, Cubbon park, and several lakes including Puttenahalli lake and Madivala lake,” he shares. </p>.<p>Ashwin Vishwanathan, a birdwatcher, viewed the phenomenon from his terrace in Kodigehalli. “I counted about 200 butterflies in a 20-metre belt within four minutes,” he shares. He started counting them just before 11 am. “After 11, it became a lot more dense,” he notes. Apart from the four main species, he also spotted Crimson Rose, Tailed Jay and some species of Sailor butterflies.</p>.<p class="bodytext">Most of the butterfly experts believe that urbanisation has not had an impact on the migration. “At the most the butterflies have probably been affected by traffic. A lot of them fly low so they get killed by moving vehicles. Pollution is also another factor that leads to exhaustion and death. But overall, I do not think it has changed things much,” says Nagaraja V, a nature photographer who is also a member of BBC.</p>
<p>Bengaluru was witness to a <a href="https://www.deccanherald.com/tags/butterfly">butterfly</a> migration last week. Many social media users reported spotting swarms of butterflies moving past apartment buildings, houses, lakes and parks. </p>.<p>They seem to have disappeared after the rains over the last two days, butterfly conservationists say. </p>.<p>Experts note that it occurs before the southwest monsoon every year. “It is said that the butterflies move to the plains and the Eastern ghats to escape the rain, for survival and reproduction,” says Srivatsan R, an environmentalist. </p>.<p>However, there is barely any scientific explanation behind their migratory patterns and routes. Ecologists call for more scientific studies on the subject, to understand the phenomenon better. </p>.<p>“Perhaps the erratic rains affect their migratory patterns. And the species that migrate are likely adapted to certain conditions, unlike other species that don’t migrate. But sadly, there is no scientific evidence to back these claims. Hopefully someone will get inspired to study them,” says Seshadri K S, an ecologist and faculty, ATREE. Though it happens twice every year ‘like clockwork’, this year the migration caught the attention of Bengalureans because “the migrating swarm of butterflies does not enter the city — we do not know the reason for this”, says Rohit Girotra, founding member of Bengaluru Butterfly Club (BBC). The last time this happened was 5-6 years back. Girotra along with a group of others spent a few hours at the Savanadurga forest last week to watch the butterflies. “We spotted the Common Crow, Double Branded Crow, Blue Tiger and Dark Blue Tiger species,” he shares. </p>.<p>Karnataka has over 350 species of butterflies. Of these, mainly four species embark on this journey, he points out. “Most of these swarms were found to be ‘roosting’ in Savanadurga forest, Lalbagh, Cubbon park, and several lakes including Puttenahalli lake and Madivala lake,” he shares. </p>.<p>Ashwin Vishwanathan, a birdwatcher, viewed the phenomenon from his terrace in Kodigehalli. “I counted about 200 butterflies in a 20-metre belt within four minutes,” he shares. He started counting them just before 11 am. “After 11, it became a lot more dense,” he notes. Apart from the four main species, he also spotted Crimson Rose, Tailed Jay and some species of Sailor butterflies.</p>.<p class="bodytext">Most of the butterfly experts believe that urbanisation has not had an impact on the migration. “At the most the butterflies have probably been affected by traffic. A lot of them fly low so they get killed by moving vehicles. Pollution is also another factor that leads to exhaustion and death. But overall, I do not think it has changed things much,” says Nagaraja V, a nature photographer who is also a member of BBC.</p>