iQi?-] Breeding-hahits of the Cuckuo. 201 



Coloration of Eggs of the Cuckoo. 



AVe now pass on to the concrete case o£ the coloration 

 of tlie ejigs of the Cuckoo, which is dealt with in the 1st, 

 3i-d, 4tli, and 5th of Dr. Key's conclusions, and the facts 

 we have to work on are as follows ; — 



(«) Dr. Rey, after exhaustive investigation, shows that 

 the legendary resemblance of Cuckoos' eggs to those of the 

 hirds in whose nests they are placed is mucli exaggerated. 

 He produces tables showing a comparison of 597 Cuckoos' 

 eggs with those of the 15 different species in whose nests 

 they were deposited. 



Of these :— 



180 or oO"2 per cent, resembled the eggs of the foster- 

 parent. 



164 or 27'5 per cent, resembled the eggs of other 

 species at times selected as foster-parents. 



209 or 35 per cent, were of a "mixed"" type, inter- 

 mediate between the eggs of two species. 

 44 or 7 per cent, were of a distinctive type of their 

 own. 



Further, of the first 180 only 7Q exactly resembled the 

 eggs of the actual clutch with which they were found, and 

 of these 57 were in nests of the Common Redstart. The 

 remaining 104 were unmistakably of the same type as those 

 of the foster-parents, but were distinct from the actual clutch 

 with which they were found. Hence we find that Cuckoos' 

 eggs exactly resembling those of the nest in which they are 

 found only amount to 13 per cent., while those resembling 

 the general type of the species selected are about 45 per cent. ; 

 but the number of species they resemble in type is limited, 

 and, according to Key, mainly comprises the Redstart, 

 Brambling, White Wagtail, and the Garden-, Reed-, and 

 Marsh- Warblers. His observations, however, were made 

 on the Continent, and in Britain the species they mostly 

 resemble are probably the Meadow-Pipit and the Sedge- 

 and Reed-Warblers. 



