NO. 9 CASQUED HORNBILLS — KILHAM 2g 



weeks later I found the same pair a mile away and still closely 

 associated. 



RELATIONS WITH OTHER BIRDS 



Hornbills became much disturbed when a hawk or eagle appeared 

 in Mpanga Forest. A crowned hawk eagle perched on a tall tree at 

 the edge of the headquarters clearing. Then he sailed into the forest 

 and was lost from view. An hour later I heard a great noise and 

 found the hawk eagle surrounded by casqued and the smaller pied 

 hornbills (Tockus fasciatus). None came closer than 20 feet. On 

 November 28 I was watching nest 8 when I heard a number of horn- 

 bills making short flights from one perch to another. This drew my 

 attention to a harrier hawk in a dead tree. Two female hornbills were 

 perched within a few feet of him, one on either side. Two males were 

 in the same tree. When the hawk flew, all four hornbills followed 

 him closely but made no noise. The bird that upset hornbills the most 

 was a great sparrow hawk. On December 11 he flew up close to me 

 in Mpanga Forest, calling "ker, kee, kee" in plaintive fashion. Three 

 male hornbills accompanied him. None of them made any noise. 

 Whenever the hawk circled and returned, the hornbills pursued closely 

 and even swooped at him. On January 2 I again heard the cry of the 

 great sparrow hawk. When he lighted above me, a male hornbill 

 lighted within 6 feet of him, and when he flew, two hornbills followed 

 within 20 feet. Hornbills are occasional predators themselves. Their 

 presence, however, seldom caused any disturbance among smaller 

 birds. I saw one hornbill momentarily beset by sunbirds and colies 

 when he was robbing a nest of the latter. Broad-billed rollers 

 (Eurystomus afer) would pursue hornbills passing by the lake shore. 

 These aggressive birds attack everything from anhingas to starlings. 



FOOD 



Fruit. — Food brought by male hornbills to their nests consisted 

 largely of fruits, ranging in size from a pea to an olive. Some fruits, 

 such as figs and pawpaw, were brought in as amorphous pieces. The 

 elliptical fruits of Canarium schweinfurthii were conspicuous and 

 prevalence of their stones on the ground were a helpful clue to the 

 location of nest trees. I was able to collect various seeds and fruit 

 stones by cleaning the ground below nests. Following is a list of all 

 fruits identified. Such indigestible matter passes through the digestive 

 tract of the hornbills and is expelled with the feces. This was observed 

 in both wild and captive birds. I have never seen hornbills go near 



