68 The Oologi sis' Record, September i, 192 1. 



an examination of the nesting hole proved to me that the Cuckoo 

 had been in difficulties also, for one of the Wagtail's eggs was lying 

 in the hole on the side of the nest. What happened is clear. The 

 Cuckoo apparently just had sufficient space to deposit her own ^^^, 

 but in removing one of the Wagtail's eggs she found the exit too 

 small. Her feathers ruffled in her endeavour to withdraw, and she 

 was glad to drop the Wagtail's egg over the side of the nest in order 

 to release herself more easily. The ^^g dropped upon chalk and 

 was fractured, probably due to the difficulty she experienced in 

 withdrawing her head from the hole. This is not the first time I 

 have noticed this with Wagtails — in fact I always examine the 

 interior of the Wagtail's nesting hole for a stray egg, especially 

 where I consider the Cuckoo has had difficulty in entering a small 

 hole. 



The tg'g I saw in the Cuckoo's throat on 20th June has interested 

 me. I do not claim it to be her own. It certainly could have been 

 the egg of the Wagtail which she was removing, carrying it away 

 in her throat to avoid detection by the Wagtails belonging to No. 2 

 nest, where she ultimately deposited her own. On the other hand, 

 it might easily have been her own, which she had intended for No. i 

 nest. It is also very interesting to note how these two female 

 Cuckoos kept the company of their five male consorts. This is 

 especially to be noticed in connection with the deposits by both 

 female Cuckoos on the nth and 20th June respectively. Once again 

 it is proved that the female Cuckoo ffiids the nests of her dupes 

 at least 48 hours before she uses them, and I hope next season, if 

 they return, to have such arrangements made as will enable me to 

 ascertain with certainty what actually happens when they enter 

 the Wagtail's nesting hole. 



