102 Proceedings of the Royal Physical Society. 
An unbiassed examination of these eggs and their foster clutches suggests 
the following observations :— 
(a) There is a resemblance in coloration both as regards intensity and 
distribution which is remarkable. 
(6) It is not surpassed nor even equalled in the coloration of the eggs 
composing the individual clutches in which the eggs have been found. 
There is noticeable variation in the different clutches of the same kind of 
bird’s eggs, e.g. Sedge Warbler’s in this collection which contrasts with the 
uniformity of appearance of the Cuckoo’s eggs of the series. 
We have here either the eggs of two or more birds, in which case a 
marvellous coincidence of colour resemblance extending to eleven eggs 
occurs; or the eggs are those of a single bird. 
If the latter alternative be correct, two facts of interest are to be noted. 
One is the confirmation of the cbservations of Baldamus and others that the 
resemblance in the eggs of the individual Cuckoo extends from one year to 
another. The second is that a single Cuckoo may lay as many as ten eggs 
in a season, and that within so short a period as twenty-two days.! 
Further, it will be noted there are four foster species involved; these 
however all nest in similar situations. The actual distance limit of this 
Cuckoo’s ovipositing operations here considered was about two miles. 
VII —Three e998, taken in Huntingdonshire. 
Museum No. Foster. Date when taken, 
1G : ; Robin . : 5 . 24th May 1913 
Ke : , Yellow Hammer . j . 24th May 1913 
K 3 : : Sedge Warbler. . 26th May 1913 
These are pale greenish eggs with brown blotching, mostly at the broad 
end. These eggs were all taken in the same area. Three foster species are 
involved. 
1X.— Three eggs, taken in Huntingdonshire. 
Museum No, Foster. Date when taken, 
L4 5 : Sedge Warbler. , 26th May 1913 
L.6 ; 5 Robin . ; ; : . 29th May 1913 
els eer. : Reed Warbler : 3 . ord June 1913 
1 Six to seven is the usual number of eggs reputed to be the product of a single Cuckoo 
ina season, I do not know upon what evidence this is based, but considering the con- 
tingencies in the matter of rearing there might well be a compensating factor in this 
species in the direction of an increased egg production. ; 
