1 9 1 7 • ] Breediyig-hahits of the Cuckoo. 211 



Finally, I may add that I do not for a moment sugs^est 

 that the Cuckoo carries her egg with her till she finds a 

 suitable nest, as this might entail a protracted journey. 

 But I think that she lays it in some concealed spot on the 

 ground, or in a tree-fork, and leaves it there until she has 

 found a nest in which to deposit it. 



The Distinctive Features of Cuckoos' Eggs. 



Passing on now to Dr. Rey's second conclusion, the dis- 

 tinctive feature of the Cuckoo's egg, as he states, is the 

 comparatively greater weight of the shell in proportion to 

 the size, its greater thickness, and different grain. The 

 colouring in many instances gives no clue, though Dr. Rey 

 says that the markings of most Cuckoos' eggs vary dis- 

 tinctly as regards the sides opposite each other, and that 

 small, distinct, round, blackish spots are a common 

 characteristic. 



Nor does the size afford any clue, the measurements of 

 6.25 eggs by Dr. Rey giving the following results : — 



Maximum : 1-00" x -70" or '98" x -72". 

 Minimum : '78" x -61" or -80" x -59". (A measurement 

 of -81" x -57" is also recorded.) 

 Average : '88" x -64". 



As regards weight, however, resulting from the greater 

 thickness and strength of the shell, we have the following 

 comparison with eggs of the Red-backed Shrike and Crested 

 Lark, which are almost identical in size : — 



Maximum Minimum , 



iveight. loeight. ^^^rage. 



grammes, grammes. grammes. 

 Eed-backed Shrike 212 148 186-5 



Cuckoo 325 165 232 



Crested Lark 230 150 191-7 



It is of interest to note in this connection that the eggs 

 of the Cow-birds are also stronger in shell than those of 

 other similar species, and vary greatly in colour and shape. 



p2 



