Malabar Gray Hornbill Ocyceros griseus
Version: 2.0 — Published July 9, 2020
Diet and Foraging
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Diet and Foraging
Consumes mainly ripe fruits of trees and lianas (and few shrubs), especially species in the plant families Lauraceae, Moraceae, Annonaceae, Myristicaceae, and Meliaceae. Fruits, usually fleshy berries, arillate drupes, and Ficus (figs), of purple/black, red, and orange/yellow color, are consumed both during the breeding and the non-breeding season (24, 25). This species also consumes animal matter (24, 20, 26).
Malabar Gray Hornbills are important seed dispersers as they disperse the seeds either through defecation (smaller seeds like Ficus) or through regurgitation (larger seeds like Myristica dactyloides). Depending on the locality and the other bird dispersers present, they are the main or only dispersers of several large-seeded tree species such as Dysoxylum malabaricum, Myristica dactyloides, and Aphanamixis polystachya (27, 23, 11).
Main Foods Taken
The Malabar Gray Hornbills mainly eat fruits of a variety of tree, liana, and shrub species, including a variety of figs (Ficus sp.) and lipid-rich fruits, along with animal matter.
Microhabitat for Foraging
The birds search for ripe fruits and animal matter in the understory, mid-story, and canopy layers of the forest. Occasionally, birds may descend to the ground to feed on fallen fruit such as Myristica dactyloides and animal prey such as winged termites.
Food Capture and Consumption
Typical feeding behavior involves picking fruits from twigs and swallowing the fruit whole with a toss of the head . However, they may also peck at and consume pieces of large fruits such as papaya, orange, and Ficus racemosa. In the case of hairy caterpillars, the birds may rub the prey on branches to remove spines before swallowing.
When feeding nest inmates, male birds usually regurgitate few to nearly 250 fruits from the gullet, delivering them one after the other by bringing it to the tip of the beak. In contrast, large animal matter may be brought alive held in the beak and delivered as single items. Animal matter may also be regurgitated.
Major Food Items
During the breeding season (February to May), Table 3 lists fruits were delivered at nests or noted in nest middens in a tropical wet evergreen forest in the Anamalai Hills (24). The following animal prey items were also delivered at the nest by the male hornbill (24):
Invertebrates: Beetle, cricket/grasshopper, cicada, stick insect, caterpillars, winged insect (wasp, termite, etc.), millipede/centipede, scorpion.
Vertebrates: Young bird, snake, lizard (Calotes sp.), gecko, frog.
Large flocks (up to 20) are sometimes noticed, particularly in the non-breeding season, where trees such as Ficus spp. and Maesopsis emenii (non-native) offer edible ripe fruits. This may include fruiting shade trees in coffee and tea plantations. In plantations in the Nilgiris, Malabar Gray Hornbills have been noted to feed on fruits of native species such as Ficus drupacea, F. tsjahela, F. virens, Streblus asper, Caryota urens, Melia dubia (M. azederach), and Piper nigrum , and fruits of non-native species such as Coffea spp. and Maesopsis eminii (26).
During the breeding season, observations at one nest indicated that items delivered at the nest by the male hornbill were predominantly lipid-rich fruits (37%), followed by figs (26%), other sugar-rich fruits (23%), and animal matter (14%). Overall, 11 kinds of fruits, 5 types of vertebrates, and at least 8 types of invertebrates were fed to nest inmates in this nest in wet evergreen forest in the Anamalai Hills (24). Another study from the Anamalai Hills region of Kerala and Tamil Nadu, recorded 62% fruit in the diet (32% fig, 30% non-fig) and 38% animal matter (insects including beetles, frogs, small snakes, caterpillars) during the breeding season (20). However, in a semi-evergreen forest in the Nilgiris in Mudumalai Wildlife Sanctuary, another study (which does not report animal matter) noted that the fruits in the diet during the breeding season were mainly non-fig sugar-rich fruits (48%) and lipid-rich fruits (47%), with figs forming only 5.3%. However, during the non-breeding season observations indicated fig fruits constituted a major part (62%) of the diet, while non-fig sugar-rich fruits constituted 12%, and lipid-rich fruits 26% (26).
Food Selection and Storage
Nutrition and Energetics
Metabolism and Temperature Regulation
Drinking, Pellet-Casting, and Defecation
Females confined in tree-hollow nests defecate outside through the nest opening (large seeds are regurgitated), forming a midden at the base of the tree. Seeds found in the midden help identify the fruits consumed by hornbills. A study at a Malabar Gray Hornbill nest in the Anamalai Hills showed that large-seeded fruit trees (such as Myristica dactyloides, Knema attenuata, Dysoxylum malabaricum, Litsea spp.) show higher regeneration under (in front of) nest trees, as compared to behind nest trees, as a result of the seed dispersal through defecation or regurgitation by the confined female and chicks ( 29 ).