26 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I3I 



His mate, who had remained silent, now began her wailing screeches. 

 I also heard her bill tapping. The intruding female, persistent as 

 usual, had followed the male back to the nest tree. In a few minutes 

 he flew at her again, flying faster than hornbills usually do as he 

 chased her from one tree to another. Five days later, mother and 

 young emerged from the nest. As already related, a foreign female 

 attacked the young bird and apparently broke its foot. After I had 

 picked up the helpless young one on March 9, I returned to the 

 Botanical Gardens late in the afternoon. The pair of hornbills were 

 perched side by side in their nest tree. Not long after I heard a great 

 flutter of wings. I looked back to see both members of the pair pur- 

 suing a foreign female. This was the last I saw of her. When the 

 parents later came to our garden, she did not follow. I have presumed 

 that the same foreign female was involved in all these incidents 

 relating to nest 5. This presumption was based on her consistent 

 behavior, general appearance, and bill shape. I never saw another 

 female with which to compare her near the tree. 



At 5 p.m. on January 26 I witnessed an intrusion by a pair of 

 hornbills. A foreign female was on the lower rim of the nest entrance, 

 poking her bill about the aperture. She made no noise. After some 

 minutes a foreign male lighted on a limb above. He had a fruit in his 

 bill tip. The female moved toward him, took the fruit, and kept 

 offering it down inside the hole. It was not accepted. The foreign 

 female would toss the fruit about in her bill, then try again. Finally 

 the rightful male returned, drove the intruding pair away, and fed 

 his mate a number of fruits. The whole incident appeared odd. I 

 wondered whether the foreign pair were unsuccessful nesters, who, 

 having a strong, though thwarted instinct to feed something, dropped 

 in on the female in nest 5. 



Interference by foreign hornbills was not limited to the nest in the 

 Botanical Gardens. It happened not infrequently at other nests. A 

 pair of hornbills were involved in each of the following intrusions. 

 On November 19 a foreign pair were perched by nest 4 in Mpanga 

 Forest. The female flew to the entrance, clinging to the lower rim 

 with tail outspread for support. She then gave some hard pecks 

 against the mud wall and grappled at bill point with the female inside 

 the nest. Neither bird made any noise. However, when the intruder 

 withdrew, the nest owner rattled her bill in the entrance. The foreign 

 male sat quietly by without participating. In a period of 10 minutes 

 the intruding female attacked the nest entrance 12 times, but did no 

 significant damage. In the next 5 minutes she attacked only twice. 

 Then the rightful male returned and drove the trespassers away. 



