<p>Hubballi: Climate change and overgrowth of vegetation have adversely impacted the world’s largest nesting grounds of river terns on the islands of Bhadra Tiger Reserve (BTR) this season. River terns, a wading bird species, are classified as vulnerable under the IUCN Red List of Threatened Species.</p><p>Researchers and forest department officials used to record more than 10,000 pairs of river terns nesting on the three to four islands in BTR between February and June. However, this year due to untimely rains in February that resulted in growth of shrubs and grasses, not even 400 of them have laid eggs.</p><p>An extended monsoon coupled with excess release of water until February has resulted in the growth of weeds on these islands, leaving early-arriving river terns with no suitable grounds for nesting. These ground-nesting birds require open sandy or rocky areas to camouflage their eggs from predators.</p><p>“Usually, the birds start arriving from December to January and stay until the arrival of the monsoon. These birds lay eggs in two to three cycles,” says head of department of Wildlife and Management, Kuvempu University, Vijay Kumar.</p>.Bengaluru airport sizzles at 38.2°C, third-highest max temperature for April since 2014.<p>He says that during this period, these islands used to remain dry, making them perfect breeding grounds for river terns. However, this year, the islands remained submerged for a longer period and were covered with vegetation, a condition typically seen during the monsoon.</p><p>Kartik N J, a research scholar at Kuvempu University who has conducted extensive studies on river terns, says that after obtaining permission from the Forest Department, they cleared a 10x10 metre patch of weeds on one of the islands to observe whether the birds would return to nest.</p><p>“During field observations, we saw that although the river terns were flying, calling and surveying the area, they were not settling down to nest as expected. The birds started nesting in the cleared patch within 24 hours of the intervention,” he says.</p><p>Our experiment confirmed that vegetation overgrowth was likely limiting nesting opportunities, and that even a minor, well-timed intervention could restore suitable breeding conditions, he says.</p><p>As the islands fall under a tiger reserve, permission from higher authorities is required to carry out weeding activities.</p><p>BTR Field Director Pulkit Meena says water levels in the reservoir remained high until the end of February. “Shrubs and grasses grew on the islands during the pre-monsoon showers, resulting in limited space for the river terns to lay their eggs. On recommendations of researchers, we cleared a patch of the island, and the birds started nesting again. Permission has been sought from higher authorities, and based on researchers’ advice, we will take measures for habitat improvement.”</p><p>He added that though the numbers may have declined this year, efforts will be made to ensure proper habitat management by the next season.</p>
<p>Hubballi: Climate change and overgrowth of vegetation have adversely impacted the world’s largest nesting grounds of river terns on the islands of Bhadra Tiger Reserve (BTR) this season. River terns, a wading bird species, are classified as vulnerable under the IUCN Red List of Threatened Species.</p><p>Researchers and forest department officials used to record more than 10,000 pairs of river terns nesting on the three to four islands in BTR between February and June. However, this year due to untimely rains in February that resulted in growth of shrubs and grasses, not even 400 of them have laid eggs.</p><p>An extended monsoon coupled with excess release of water until February has resulted in the growth of weeds on these islands, leaving early-arriving river terns with no suitable grounds for nesting. These ground-nesting birds require open sandy or rocky areas to camouflage their eggs from predators.</p><p>“Usually, the birds start arriving from December to January and stay until the arrival of the monsoon. These birds lay eggs in two to three cycles,” says head of department of Wildlife and Management, Kuvempu University, Vijay Kumar.</p>.Bengaluru airport sizzles at 38.2°C, third-highest max temperature for April since 2014.<p>He says that during this period, these islands used to remain dry, making them perfect breeding grounds for river terns. However, this year, the islands remained submerged for a longer period and were covered with vegetation, a condition typically seen during the monsoon.</p><p>Kartik N J, a research scholar at Kuvempu University who has conducted extensive studies on river terns, says that after obtaining permission from the Forest Department, they cleared a 10x10 metre patch of weeds on one of the islands to observe whether the birds would return to nest.</p><p>“During field observations, we saw that although the river terns were flying, calling and surveying the area, they were not settling down to nest as expected. The birds started nesting in the cleared patch within 24 hours of the intervention,” he says.</p><p>Our experiment confirmed that vegetation overgrowth was likely limiting nesting opportunities, and that even a minor, well-timed intervention could restore suitable breeding conditions, he says.</p><p>As the islands fall under a tiger reserve, permission from higher authorities is required to carry out weeding activities.</p><p>BTR Field Director Pulkit Meena says water levels in the reservoir remained high until the end of February. “Shrubs and grasses grew on the islands during the pre-monsoon showers, resulting in limited space for the river terns to lay their eggs. On recommendations of researchers, we cleared a patch of the island, and the birds started nesting again. Permission has been sought from higher authorities, and based on researchers’ advice, we will take measures for habitat improvement.”</p><p>He added that though the numbers may have declined this year, efforts will be made to ensure proper habitat management by the next season.</p>