Factors influencing distribution and habitat utilisation of Leptoptilos javanicus in and around Barandabhar Corridor Forest, Chitwan, Nepal

Yureshiya Wagle,Jagan N Adhikari,Bishnu P Bhattarai

doi:10.24189/ncr.2022.005

Abstract

The globally Vulnerable wetland-dependent bird species Leptoptilos javanicus was once thought to avoid farmlands, but recent studies in lowland Nepal showed that the species uses farmlands extensively for foraging and breeding. Identifying whether this preference of L. javanicus to these habitats is common throughout Nepal is essential to understanding the conservation needs of the species. This study aimed to explore the seasonal distribution and habitat utilisation by L. javanicus in and around the Barandabhar Corridor Forest by using 220 randomly selected squares within a 500 × 500 m2 grid. We visited centroids of each selected square to collect data on L. javanicus distribution, habitat types, and probable causes of disturbance in two seasons (rainy: August – September 2019 and winter: December – January 2019–2020). A total of 64 observations of L. javanicus (n = 29 in winter, n = 35 in rainy) were made. Leptoptilos javanicus were seen in more squares outside the Protected Area (65.2%) during the rainy season. Variables that negatively influenced L. javanicus sightings were distance to the road (few individuals seen close to the road), distance to the village (few individuals seen close to settlement), and areas under human disturbance (only few individuals seen in areas with more livestock and people) during both seasons. The farmlands around the Barandabhar Corridor Forest hosted many individuals of L. javanicus and are a new location in lowland Nepal with a resident population of this species. Past assumptions regarding L. javanicus conservation require revision, and including a focus on farmlands is an important requirement in Nepal's conservation planning.

Highlights

The Lesser adjutant, Leptoptilos javanicus (Horsfield, 1821), is a large wading bird of the Ciconiidae family with an estimated global population of 5000–10000 individuals (BirdLife International, 2017)
Distribution of Leptoptilos javanicus No records were found from the squares located in the farmlands of the drier north-west region of Barandabhar Corridor Forest (BCF)
Our study provides additional primary information that suggests that L. javanicus is able to use agricultural areas much more than forested areas

Summary

Introduction

The Lesser adjutant, Leptoptilos javanicus (Horsfield, 1821), is a large wading bird of the Ciconiidae family with an estimated global population of 5000–10000 individuals (BirdLife International, 2017). Grasslands, marshes, water holes, lagoons, flood plains, dams, flooded pastures, rivers, streams, lakes, and ponds are habitats used by this species (del Hoyo et al, 2020) They use undisturbed moist forests with tall trees for breeding and roosting (Hancock et al, 2010). Leptoptilos javanicus is assumed to be declining globally and nationally in Nepal with suspected causes being habitat loss and degradation, illegal hunting, human activities such as timber, firewood, grass collection, livestock grazing (Inskipp et al, 2016; BirdLife International, 2017). The National Parks and Wildlife Conservation Act of 1973 in Nepal (NPWC Act, 1973) has yet to list this species as a nationally protected bird species (DNPWC, 2020)

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