6 Transactions of the South African Philosophical Society. 



remains open, although I could not imagine how she managed it. 

 But as the female to which I referred had her beak covered with it, 

 some of her excrements were taken out of her anus for comparison. 

 They looked very different from any other excrements of birds I have 

 seen. They felt sticky to the touch, and when dry they presented 

 exactly the same appearance as the cement with which I am very 

 familiar, except, of course, that there were no bits of wood embedded 

 in it. I feel now almost convinced that the female constructs her 

 own prison, and I begin to doubt whether the male bird has any 

 essential share in it. However, as only the lowest portion of the 

 ceiling in the nest belonging to type No. 2 could have been con- 

 structed by the female, the upper loose portions must evidently have 

 been put in by the male, and it must therefore be left to further 

 observations to decide whether he also uses his excrements in the 

 same manner as the female does, since this case shows, at all 

 events, that he must take some interest in the construction of the nest. 

 There is not very much room in a nest when the female is alone, 

 and one can easily imagine that it would be a very tight fit if she 

 was to occupy it with three or four nearly full-grown young ones ; 

 besides, the supply of food for three or four such large birds might 

 even overtax the strength of the most devoted father of such a 

 family. The question therefore arises, Does the female leave the 

 nest before the young ones are quite capable of taking care of them- 

 selves ? and if she does so we have further to ask whether the nest 

 is closed up again, and by whom this is done ? The only nest which 

 arrived late in the season last year was the one found in the Kap 

 Eiver Valley, near Clumber. It was brought to me about the 10th 

 of February by Mr. W. Webb. Unfortunately he had removed 

 the cement to prevent it from being broken on the journey, but he 

 was positive that no bird had escaped from it, as he had carefully 

 closed up the entrance again. When opened, the nest was found to 

 contain a nearly full-grown young bird. As Mr. Webb is known to 

 be a trustworthy man, I had no hesitation in concluding from his 

 statements that the female left the nest some time before the young 

 one was fully developed and helped the male to feed it, and that the 

 entrance was closed up after her exit in the usual manner, most 

 probably by the young bird. This conclusion was strikingly con- 

 firmed by a nest which I received this year on January 19th. It 

 was perfectly intact ; no bird could possibly have left it on the 

 journey to Grahamstown, but when it was opened it was found to 

 contain only two young birds which were still far from the stage at 

 which they would be able to fly. The female had left the nest, but 

 the entrance was plastered up again in the ordinary fashion. Thus 



