NO. 9 CASQUED HORNBILLS — KILHAM I9 



entrance. When the male bent over to offer food, she would not always 

 bother to turn around. One day he gave her a fresh green leaf before 

 coughing up four yellow fruits. At nest 12, also at Mpanga, the 

 female would put her whole bill out of the entrance to take food. 

 Possibly females in these last two nests were crowded for space. 

 Some of the holes, such as those of nests 4 and 7, were on straight 

 trunks without boles. Consequently, the visiting males had to cling 

 to the lower rim of the nest with tail fanned out against the trunk. 

 An occasional visiting male would bring bark to his mate but no food. 



Expulsion of feces, and other activities of female in nest. — Watch- 

 ing and listening from the ground gave some insight into activities 

 of nesting females. At infrequent intervals one might see a stream of 

 fecal matter shoot 2 to 3 feet out of an entrance hole, glisten in the 

 sun, then land with a splash on the leaves below. The white feathers 

 of the female's rear end were, in some nests, clearly visible as she 

 maneuvered her vent to the opening. Hornbill vents are protrusible 

 and mobile. This could be well seen in our young birds 6 to 8 weeks 

 of age when, standing way up on their legs, they would back up over 

 the edge of the box they were in and expel feces on the floor. Expul- 

 sion was not as forceful as seen in some hawks. Tree trunks and 

 foliage below nests were not appreciably stained by expelled feces. 

 This was partly due to the dark color of the droppings resulting from 

 a fruit diet. Some streaking of white appeared in feces with develop- 

 ment of the young. On January 8, as I was sitting on the scaffold be- 

 side nest 10 in Mpanga Forest, the 4-weeks-old chick backed to the en- 

 trance and deposited a cylinder of feces 4 inches long on the lower 

 cement. This feces had a white film over one end. The ladder leading 

 to nest 10 became increasingly spattered with feces as weeks went on. 

 Observations on my captive birds indicate that the white substance 

 in the feces increased with ingestion of animal protein. I saw one 

 nesting female toss debris out of the entrance with her bill. Doubtless 

 this method also contributes to nest sanitation. 



Females within the nest did not lose their constructive instincts. 

 Bill tapping continued, but was carried on far more by some females 

 than others. I frequently heard tapping from nests 7 and 10, which 

 were only 120 feet apart, at the same time. Much of the time I could 

 not see a bill in the aperture. It is conceivable that these birds plaster 

 debris against their nest cavities either because habit is strong or just 

 by way of idle amusement. My young captive hornbills plastered the 

 walls of their cage, possibly for the same reasons. Entrance walls, 

 however, sometimes needed repair. On November 28, the female of 

 nest 6 was repairing her nest entrance at noontime. I could see her 



