THI: CUCKOO'S FOSTER-PARENTS AND EGGS ..-. 



in >i/t> relativeh t that n\' tin t.^i, r pan-nt- _j- Thus while 

 robins' eggs average 17*7 x 12*7 mm. and hedge-sparrows' 80*1 x 14*7, 

 ruck..,,- -ggs from the former average 21*1 x 15X and from the latter 

 H x 16-a 



With regard to the quest ion as to the number of eggH laid by 

 each hen cuckoo in the course of the season, we find great disorep- 

 ancies in the conclusions at which different writers have arrived. The 

 tendency of most of the earlier writers on the subject was in favour 

 of a small number of eggs, ranging from 4 or 5 to 7, laid at intervals of 

 six to eight days. But Dr. Rey's researches led him to the astonishing 

 conclusion that each female cuckoo laid about 20 eggs every year, 

 and that they were deposited on alternate days. J. A. Link, on the 

 other hand, believes that the long series of eggs of one type collected 

 by Or. Rey and hie son in single seasons were probably the produce 

 of two hens which laid very similar eggs. V. Capek, in a very careful 

 paper in the Ornitholoyixche JaJirbuch for 1896, is of opinion that the 

 cuckoo lays on alternate days, but that the eggs are deposited at 

 two periods, with an interval between, as in the case of birds which 

 are ordinarily double brooded. He believes that a hen in full vigour 

 lays 5 to 7 eggs on alternate days during the first period, while, after a 

 short pause, a second series of eggs, probably from 4 to 5 in number, is 

 deposited, but at longer and probably irregular intervals. On the 

 whole this seems to be the most satisfactory elucidation of the facts, 

 and is not inconsistent with the facto as recorded both in England 

 and on the Continent It must be remembered tliat the accurate 

 study of this subject can be carried on in some |>arts of the Continent 

 far more satisfactorily than with us. Thus in the neighl>ourhood of 

 Leipzig, where Dr. Rey worked, the redlweked-shrike is the most 

 la\ oured foster-parent of the cuckoo. But the whole country round 

 i- arable, entirely devoid of hedgerows, and only here and there are 

 small plantations to be found, where the shrikes must necessarily 

 breed. It is therefore not impossible for two active men to be 

 personally acquainted with every nest of the shrike for a wide radius. 



