Buxa home to over 8.5k hornbills, key species score high in Mahananda belt

Kolkata: In a first, a long-term study for abundance and density estimation has been done for hornbills in Bengal. The study conducted between 2018 and 2024, covered north Bengal's Buxa Tiger Reserve, Mahananda Wildlife Sanctuary, Latpanchar, a fringe village outside Mahananda, Neora Valley and adjoining forests of Kalimpong.Bengal is home to five species of hornbills — great Indian hornbill, rufous-necked hornbill, grey hornbill, oriental pied hornbill and wreathed hornbill.The study is a Nature Mates-Nature Club and Nature Conservation Foundation collaboration, currently funded by Habitat Trust. While Buxa and Mahananda have scored high in terms of density-abundance and encounter rate of oriental pied hornbill — considered to be among the smallest of Asian hornbills — Latpanchar has recorded good density of rufous-necked hornbills — considered ‘vulnerable' on IUCN Red list."To estimate hornbill density, abundance and distribution in Buxa, an occupancy-based survey was done over Sept-March of 2019-2020 and 2020-2021," said Sitaram Mahato of Nature Mates. "The estimated density of the three large-bodied species was low — less than 1 bird per sqkm — while that of the oriental pied hornbill was around 11 birds per sq km. Abundance estimates — number of individuals in a population — ranged from a mean of 27 birds for rufous-necked hornbill, 161 for great hornbill, 375 for wreathed hornbill and 8,050 for oriental pied hornbill at Buxa," said Shilpita Mandal of Nature Mates. Since Dec 2021, transect surveys to estimate hornbill population, abundance in Latpanchar, a fringe village of Mahananda located at an elevation of 1,100 m, was also conducted. From Dec 2021 to Dec 2023, in a total effort of 344.9 km, density estimate for rufous-necked hornbill was 9.6 /sq km. "Average encounter rates for direct sightings of Rufous-necked hornbill was 0.3/km and for the great hornbill was close to 0.1," said Kesang Dukka of Nature Mates."We also conducted a park-wide survey in Mahananda between Nov 19 and Dec 12, 2023. In a total effort of 40.5 km, there were 16 detections of oriental pied hornbill. There were 5 detections of great hornbills. But, during the survey, there were no detections of rufous-necked and Indian grey hornbill. Overall encounter rate (detections/km) for oriental pied hornbills was 0.4/km. The same for great hornbills was 0.1/km," NCF's Karishma Pradhan said, adding that in 2018, in a rapid survey at Neora Valley, there were at least 10 detections of rufous-necked in an effort of about 60 km.It also highlighted breeding biology of hornbills, with nesting success of 81% in Buxa and 88% in Mahananda-Latpanchar. Hornbill conservation action plan was done with funding from Conservation Leadership Programme.