Weight of Cuckoos' Eggs. 31 



through a wider range of colour than those of any 

 other bird. 



As to size, the eggs are on an average only one- 

 fourth of that expected from the size of the bird, 

 though in weight, as the careful tests of Mr. Bidwell 

 as well as my own undoubtedly show, the eggs are 

 much heavier than any eggs of the same size. Dr. 

 Rey, too, dwells on the weight of shell of egg of 

 Cticulus canorus. 



This fact would be remarkable enough even did it 

 not bear on remarkable facts beyond it. The habits 

 of the foster-birds as to nests vary so vastly that it is 

 hardly credible the young of one species could thrive 

 in all — in open nests, in domed nests, nests hung over 

 water or moist places as with the Reed-wren and 

 Sedge-warbler, nests high in trees, nests low in shrubs 

 or even on the ground like those of the nightingales 

 and larks. 



A list of 120 species in which cuckoos' eggs have 

 been found is published by Mr. Bidwell in the Bulletin 

 of the British Ornithologists' Club for March, 1896. 

 But adaptation and resource are everywhere con- 

 spicuous. The cuckoo, when he cannot find his 

 favourite nests, makes others, and apparently un- 

 promising ones, suit him equally well.''' 



* The most notable in regard to numbers of eggs from nests 

 of each species, in his collection of over 900, being : — i, Hedge- 

 sparrow, 74 ; 2, Redbreasts, 65 ; 3, Reed-warblers, 62 ; 4, Mea- 

 dow-pipits, 49 ; 5, Garden- war biers, 47 ; 6, Sedge-warblers, 41 ; 

 7, White-Throat, 38 ; 8, Pied Wagtail, 34 ; 9, Blackcap, ^^ ; 10, 

 Tree-pipit, 33 ; 11, White Wagtail, 32 ; 12, Red-backed Shrike, 

 25 ; 13, Yellow Bunting, 23. N.B. — Mr. Bidwell tells me that 

 among the 74 from Accentors' nests was a blue egg, taken by 

 Mr. Robert H. Read, a well-known and reliable ornithologist. 



