5° British Birds, with their Nests and Eggs. 



Mr. Bidwell's study of the habits of this bird has led him to the conchtsion 

 that it laj'S five eggs in a season at intervals of seven or eight days. It is not 

 at all improbable that this ma}^ sometimes be the case, but Mr. Harper's experience 

 quoted above seems to show that the habit is not invariable ; moreover, as recorded 

 in my " Handbook " (p. 103) a friend of mine took five eggs in one evening, all 

 so much alike that, presumabl}^ they represented the clutch of one bird, in a 

 swampy grove at the village of Tong, near Sittingbourne, and all from nests of 

 the Sedge Warbler : none of these eggs were much incubated, indeed they were 

 all blown with ease, so that there could have been no such interval between the 

 dates at which they were deposited. 



It is extremely probable that five represents the normal clutch of the Cuckoo, 

 and Mr. Rowle3^'s studies led him to the conclusion that the time of nidification 

 extended from the beginning of May to the middle of Jul}-, but in Kent I have 

 only found the eggs from the middle of May to the end of June. 



As a rule the eggs of this bird are coloured and marked much like eggs of 

 the Pied Wagtail, the Greater Whitethroat, pale varieties of the Sky- Lark, etc., but 

 sometimes the_v greatly resemble the eggs with which they are deposited, even 

 when the latter are utterly dissimilar from the normal type : thus I took a clutch 

 of Robin's eggs containing that of a Cuckoo remarkably resembling those of the 

 foster-parent, whilst Seebohm, William Borrer, of Cowfold, Sussex, and others have 

 taken pure blue eggs deposited with those of the Hedge-Sparrow, Redstart, etc.* 

 In almost all eggs of the Cuckoo there are tinj' rounded slate-coloured spots 

 towards the larger end, although in blue eggs these spots are frequently almost 

 obsolete. 



Of the eggs figured on pi. viii, figs. 269, 271, 272, 275, 276, 278, 280, 283, 

 284, 285, 286, and 288 are from Mr. A. B. Farn's collection; 270, 274, 277, 279, 

 287, and 289 are from my own series, and 273, 281, 282 from that of Mr. Frohawk. 



In the fine series which we have figured, it will be seen that the egg varies 

 remarkably even when deposited in nests of the same species, and generally, when 

 placed in a Hedge- Sparrow's nest, the}^ are so little like those laid by that bird, 

 as to make one wonder that they are not ejected. 



It has been suggested, as an explanation of the fact that the eggs of the 

 Cuckoo sometimes resemble those of its foster-parents, that the parents for gen- 

 erations past had been reared by the same species, and that the similar feeding 

 and treatment had in some inexplicable manner affected the deposition of pigment. 

 If this be a fact it is no marvel if these assimilations are rare, for it would seem 

 to necessitate a condition of things which is well nigh impossible, viz : — that both 



* From one of these Seeboiim extracted a young Cuckoo, recognizable at once by the character of its feet. 



