Abstract: The Malabar Grey hornbill (Ocyceros griseus) is a frugivore, endemic to the tropical rainforests and moist and deciduous forests of the Western Ghats hill ranges, India. The author studied its breeding biology in the Annamalai hills (Indira Gandhi Wildlife Sanctuary), Tamilnadu state, by monitoring 10 nests and theirs middens, and conducting intensive observations at a focal nest. The nesting period lasted an average of 86 days (N=4), and observations at the focal nest revealed the pre-and post hatching phases to be 40 and 60 days, respectively. At the end of nesting period, the females and the young simultaneously broke out the nests. A total of 2397 items of food were delivered by the male hornbill to the inmates of the focal nest. They included 6 species of lipid-and 8 species of sugar rich fruits, and at least 14 kinds of animal matter. Lipid -rich fruits formed a major component (37%) of the diet during nesting. Ficus fruits formed 26%, and animal matter 13.8% of the diet if the increased hornbills.the frequency of sugar -and lipid -rich fruits delivered per hour of observation was higher in the post hatching phase. Although the Malabar Grey hornbill used a wide range of food resources,it was observed that a few species of rare, tropical trees producing lipid-rich fruits during the nesting period, play an important role in the maintenance if the species.