Behavioral Pattern of Endemic Sri Lanka Grey Hornbill (Ocyceros gingalensis) within the Breeding and Nonbreeding Seasons

Abstract

The hornbills are among the most extraordinary looking birds in the world. Out of two species of hornbill, the Ocyceros gingalensis is the only endemic grey hornbill in Sri Lanka. This study was conducted in Mihintale Sanctuary which is comprised of secondary dry mixed evergreen forest patches and semiurbanized area from 2013 to 2015. Ad libitum focal animal sampling was used to construct an ethogram for the behavior of Sri Lanka grey hornbill (SLGh). The study recorded 35 behavioral events in 11 acts under 4 types of their activities. Courtship and mating activities were recorded within the study period. Food items were changed throughout the parental care period. Within this period chicks were offered sufficient food comprised of fruits and flesh. These revealed that the nesting of the SLGh in suburb areas is not good sign since it potentially indicates the loss of adequate breeding conditions in the forest. Conservation of SLGh depends on protection of trees and tree cavities as an important ecological niche.

Food availability and food selectivity of Sri Lanka Grey Hornbill Ocyceros gingalensis Shaw, 1811 in Mihintale Sanctuary, Sri Lanka

“…March to June was recognized as the breeding season of SLGH (Wijerathne & Wickramasinghe 2018) in the Dry Zone. The study period was selected to represent both breeding and non-breeding (post fledging) stages of the life cycle from 2015 to 2016.…”

“…The study period was selected to represent both breeding and non-breeding (post fledging) stages of the life cycle from 2015 to 2016. Nine nest cavities were identified in the study site, mostly on the periphery of the forested areas (Wijerathne & Wickramasinghe 2018, 2019. The volume of fruits (fruiting species and the number of fruits consumed from each species per observation time slot) consumed by selected individuals (ringed male hornbills during 2011 by field ornithology group of Sri Lanka) within non-breeding and breeding J TT seasons were noted using the scan sampling method (Simpson & Simpson 1977) for generating fruit selectivity (Lamperti et al 2014) index (Krebs 1973).…”

“…Locations of nine nest cavities of SLGH were identified based on the previous studies conducted by Wijerathne & Wickramasinghe (2018, 2019. Three nests were selected from the above for frequent weekly nest feeding observations.…”

“…Nutrient analysis of the two selected types of fruits which were observed as preferable and non-foraged by SLGH (Wijerathne & Wickramasinghe 2018) were used to test the selectivity influenced by the available nutrient capacity. Due to limitations of chemicals and equipment, all available fruits of the area could not…”

“…Though Wimalasekara & Wickramasinghe (2014) observed and mentioned SLGH as an arboreal frugivore in the Mihintale Sanctuary, there are no records of dietary requirements during the breeding season. Due to the lack of scientific and systematic breeding biological records of this bird (Kotagama et al 2011;Wijerathne & Wickramasinghe 2018), this study was conducted to cover both the breeding and non-breeding periods of the lifecycle specifically to highlight the food availability and selectivity patterns in the Dry Zone of Sri Lanka. The main objective of the study is to understand the patterns of dietary requirements at different stages of the lifecycle and food selection factors as with the influence of available fruiting trees in the area specially to fill up the remaining gaps in the avian ecology of the Dry Zone forests.…”