HORNBILL ABUNDANCE IN UNLOGGED FOREST, SELECTIVELY LOGGED FOREST AND A FOREST PLANTATION IN ARUNACHAL-PRADESH, INDIA

The responses of hornbills to selective logging were determined by com paring their diversity and abundance in five habitats classified accor ding to logging history. Relative abundance of three hornbill species was compared along trails in recently logged forest, 20-25-year-old lo gged forest, unlogged primary forest, a relatively disturbed primary f orest and a plantation in Pakhui Wildlife Sanctuary and adjoining rese rve forests in western Arunachal Pradesh. The species recorded were th e Oriental pied hornbill Anthracoceros albirostris, wreathed hornbill Aceros undulatus and great hornbill Buceros bicornis. The great hornbi ll was the most common species overall and its abundance varied across habitats, being highest in unlogged forest. The Oriental pied hornbil l, which was recorded in only two habitats, seemed to show a distinct habitat preference for secondary growth, river-margin forests. Wreathe d hornbill abundance did Mot differ between habitats. Differences in s pecies abundance probably reflect aspects of their ecology, such as de gree of territoriality, diet and movement patterns, and differential v ulnerability to hunting and disturbance. Great hornbill abundance was correlated with large tree density (GBH greater than or equal to 150 c m) and basal area characteristic of unlogged primary forests, while Or iental pied hornbill abundance was negatively correlated with tall for est, indicating its greater numbers in low-stature river-margin forest . Wreathed hornbill abundance was not correlated with any vegetation v ariable, which is probably related to its reported nomadic movements i n search of fruit patches. Hornbill abundance was not correlated with densities of potential food and nest tree species. Although hornbill a bundance was not correlated with fig tree density, this was probably b ecause areas where relative fig tree densities were lower often contai ned a few large fruiting figs. Because hornbills are large mobile bird s, they can find resources such as fruiting figs even in otherwise uns uitable habitat.