NO. 9 CASQUED HORNBILLS — KILHAM 3I 



directly to the hole. One male repeatedly drove his bill into the exca- 

 vation. I was not sure whether the barbet was inside or not. For the 

 next 15 minutes the hornbills quietly examined the hole, knocked off 

 dead bark, and searched leaves and seed pods. Their hunting was not 

 successful while in the garden. However, hornbills probably catch 

 other birds on occasion. On January 29 a male in Mpanga Forest 

 glided to his nest with a sparrow-sized bird, chewed beyond recogni- 

 tion, hanging from his bill. He saw me and quickly flew away. My 

 captive hornbills have been maintained to a large extent on left-over 

 laboratory mice which they swallow whole. They appear to thrive on 

 animal protein. 



Hornbills catch insects both large and small. I found the remains 

 of some insects which they had fed upon by examining fecal matter 

 below nest 5 in the Botanical Gardens. Dr. V. G. L. van Someren 

 was able to identify the following: 



REMAINS OF INSECTS RECOVERED FROM FECES BELOW HORNBILL NEST 5 



Dicranorrhina micans (Drury) 



Longicornis beetles of cerambycid group 



Rhyparohia grandis (Sauss.) — large cockroach 



Long-horn cricket 



Tenebrionid beetle, Mctallonolus 



Slender-winged mantis 



Some were not adequate for species identification. Large bark beetles 

 were a frequent finding. Activities of a male hornbill observed on 

 February i indicated how these might be captured. For a half hour 

 in midmorning he worked on the dead portion of a large tree. He 

 would strike slanting blows to loosen a piece of bark, then pry under 

 it and appear to pick out something from underneath. The next step 

 was to knock the loose bark to the ground. This hornbill showed 

 acrobatic skill, often leaning way over on its long legs, with head and 

 neck outstretched, in an effort to reach more bark. He removed at 

 least 3 square feet before flying away. Praying-mantis nests were 

 not infrequent in accumulations below nest 5. They had come through 

 the digestive tract more or less intact, as indicated by adherent feces, 

 I would not have supposed that casqued hornbills could catch small 

 insects on the wing. They are, however, quite resourceful in this 

 respect. On April 18 three hornbills were perched on a casuarina tree 

 late in the afternoon. They were gulping at a close swarm of insects 

 that were whirling about in a small cloud near the treetop. These 

 insects were black-winged termites. Some were still moving upward 



