128 Mr. C. F. M. Swyunertoii on Rejections [Ibis, 



in the two seasons, and this summary of them was written 

 while the later details were still fresh in my mind. 



The figures I shall refer to are those of Plate XIX. in 

 'The Ibis' for October 1916. 1 hoj^e to figure later some 

 of the actual eggs used. 



I have found it very neoessarj^ for convenience and 

 clearness, to coin single word-terms to denote (1) birds 

 that lay only one type of egg (with its variations), and 

 (2) birds that lay two or several distinct types, as do 

 many Cuckoos, Weavers, and Warblers. On the analogy 

 of botanical usage, I am using the adjective " homoic " 

 for the former and " heteroic " for the latter. 



Results of the Experiments. 



1. Acceptances of channeling eggs occurred. — Among other 

 instances, a Lark-heeled Cuckoo {Centropus burchelli) , 

 laying pure white dove-like eggs, accepted and sat on a 

 brown Fowl's egg weighing twice as much as one of her 

 own ; a Cisticola natalensis, with very pale, unspotted, 

 blue eggs, accepted an egg of Pycnonotus layardi, again 

 twice as large as her own and coloured like a Tree-Pipit's 

 (c/. fig. 16) ; a Coly (C siriatus minor : fig. 2) accepted 

 and retained a Canary's egg (Serinus shnrpei) with black 

 spots, and a Tarsiger stellatus (Robin-like) a Coly's ; and 

 Thick-billed Weavers {Amblijospiza aWifrons, nearest fig. 14) 

 took back eggs of their own, the appearance of which had 

 been modified by the addition of blotches or smears of 

 brown-madder water-colour paint. 



2. Such acceptance ivas not necessarily final. — I placed 

 a Layard Bulbul's egg, of the type shown in fig. 11, 

 in a nest containing tAvo eggs of Telephonus senegalensis, 

 removing (as usual) one of the latter (white,- with a 

 heavy sepia cap). The Shrike returned, perched on the 

 side of the nest and, leaning over, manipulated one 

 or both of the eggs with her bill, then quietly settled 

 down on to them atid sat steadily. On my revisiting the 

 nest later, the Bulbul's egg was gone and the Shrike 

 was sitting on its one egg only. This was the last egg 



