Nesting habitat selection and challenges of conservation of the vulnerable Lesser Adjutant Leptoptilos javanicus (Horsfield, 1821) in the Chitwan National Park, Nepal

Abstract

The nesting ecology and conservation threats of the Lesser Adjutant (Leptoptilos javanicus) were studied in the Chitwan National Park, Nepal. We located nine nesting colonies during the nesting season. The number of nests was highly positively correlated with tree height, diameter at breast height and canopy cover. The uppermost canopy of the trees was the most preferred nesting place. Storks preferred to nest in compact colonies on large, widely branched trees with thin foliage cover, such as Bombax ceiba, and also nearby the foraging grounds such as wetlands and grasslands. Storks mostly preferred to nest in Bombax ceiba, but if this tree was not available, they nested in other trees, such as Shorea robusta, Ficus racemosa and Terminalia alata. During the breeding season, 180 adults, 76 nests and 88 chicks were recorded, where the highest number of chicks was recorded near the Sauraha area of the Chitwan National Park. Most of the colonies were far from human settlements, which suggest that human disturbance could be the major determinant of nesting habitat selection in this area. The wetlands nearby human settlements are either overexploited in terms of mass collection of the storks` prey species by people or disturbed highly due to presence of a large number of people. These empirical findings suggest that conservation of Lesser Adjutant mainly rely on the protection of mature Bombax ceiba trees and the reduction of human disturbance and of the collection of stork prey animals from foraging areas.

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

“…Disturbance factors such as distance to roads appear to negatively impact the presence of L. javanicus in the study area in the rainy season. Similar findings were made previously by Bhattarai et al (2021) in Chitwan National Park of Nepal. Karki & Thapa (2013) also reported a negative relationship of L. javanicus in eastern Nepal with human settlements and roads.…”

“…More individuals of Leptoptilos javanicus were seen during the rainy season than in winter. During the rainy season, L. javanicus was seen more regularly on farmlands in the CNP buffer zone, where the species had previously been observed (Poudyal, 2010;Bhattarai et al, 2021). However, during the winter season L. javanicus was found to be largely using forest areas while also using other habitats (Fig.…”

Factors affecting the breeding ecology of the globally threatened Lesser Adjutant (Leptoptilos javanicus) in agricultural landscapes of Nepal

“…Our study provides insights into the importance of nest tree species and height-and colony-level variables on the breeding of the Lesser Adjutant. Our study further demonstrates the value of Nepal's agricultural landscapes for breeding Lesser Adjutants that were incorrectly assumed to require forests and protected wetlands (Poudyal and Nepal 2010, Inskipp et al 2016, Bhattarai et al 2021. We were able to confirm that the largest breeding populations are in central Nepal, where previous studies were conducted (see Sundar et al 2019, Koju et al 2020.…”

“…The Lesser Adjutant (Leptoptilos javanicus) is another large waterbird species (Fig. 1) that was, until recently, assumed to require undisturbed forests and wetlands for its breeding (Poudyal and Nepal 2010, Inskipp et al 2016, BirdLife International 2021, Bhattarai et al 2021. Relatively few studies have been conducted on the ecology of this species (Table 1).…”