Family CUCULIDAE. 



Cuculus canorus L. — Cuckoo. 



(Plates 89—90, fig. a— 1). 

 (Snouckaert: Avifauna Neerlandica, p. 57, No. 137). 



Colour of surface of shell: 



Colour of spots: 



Average dimensions: ') 

 Average weight of shell: 



Nature of shell: 

 Texture of shell: 

 Shape : 



Species of birds, with which 

 canor us-eggs are found: 



Probable number of eggs in one 

 season : 



Breeding season: 



Duration of incubation by the 

 foster parents: 



yellowish, greyish, reddish, or greenish white; 

 greenish; bluish; greenish, reddish, violet, 

 or brownish grey; brownish ; red; pale blue; 

 bright bluish green (with as well as with- 

 out reddish yellow specks or spots when 

 of this latter colour); pure plain white 

 (extremely rare: only a few are known from 

 works on the subject). 



grey; greyish green; greenish, reddish or 

 greyish brown; reddish yellow; rusty red ; 

 light or dark brown; blackish brown; 

 when lying deeper they are of a greyish 

 or violet grey appearance. 



22.4 X 16.5 millimetres. 



0.231 gram. Particularly large eggs of Ph. 

 phocnicurus and 5. oenanthe can always 

 be distinguished from bluish green eggs 

 of canorus by their weight. 



characterized by a special firmness. 



see general review. 



usually blunt oval; sometimes almost elliptic 

 (see further the characteristics sub 6 in 

 the general review. 



see general review. 



according to some, about 8, and to others 

 about 20 is the maximum. (See general 

 review). 



May— July, 

 about 11 days. 



») See my reference to LATTER'S „Statistical investigations respecting the dimensions of 

 Cuckoo eggs", in „Verslagen en Mededeelingen der Nederlandsche Ornithologische Vereeniging", 

 No. 1 (1904), pages 52, etc 



