Ege Coloration in the Cuckoo, Cuculus canorus. 99 
conclusion can be drawn as to their origin, so remarkably similar are the 
eggs, than that they are the product of the same bird. In most cases the 
groups of eggs, arranged on the basis of locality and near dates, show 
distinctly more agreement as regards size and colour than do the foster eggs 
within the individual clutches. The following are illustrations :— 
I.—Two eggs taken at Budworth Mere, Cheshire. 
Museum No, Foster. Date when taken. 
PAG G)/2) . Reed Warbler . f . 29th May 1910 
A6/3.. : . Reed Warbler . : . 5th June 1910 
These eggs are of a bluish-grey colour, with dull brownish blotching ; 
there are abundant fine dots and also numerous larger specks of varying 
shape and size. The eggs are not noticeably darker in colour at the broad 
end. The two eggs cannot be distinguished. There is one foster type only. 
Il.— Four eggs taken at Budworth, Cheshire. 
Museum No. Foster. Date when taken. 
Gall”: , . Sedge Warbler . : . 8th June 1910 
GiGi. . Reed Warbler . : . 10th June 1910 
CVG) aa . Sedge Warbler . : . 13th June 1910 
G6/9. ‘ . Reed Warbler . : . 18th June 1910 
These are pale grey eggs with finely grained brown markings. There are 
numerous sharply defined dark brown spots. The resemblance is most 
marked in all four eggs. There are two types of foster in this case. Taken 
in conjunction with the foregoing set two Cuckoos are indicated in this area. 
ILL.—Set of two eggs, presumably of the same bird, taken near Lancaster. 
Museum No. Foster. Date when taken, 
D11/3 . : . Yellow Bunting . : . 22nd May 1912 
D 13/2. : . Hedge Sparrow . 5 . 27th May 1912 
This is a greyish egg with a good deal of brownish pigment in fairly 
large irregular patches well distributed evenly over the whole egg, but more 
deeply at the broad end. There is a brownish speckling over the whole end 
area in both eggs—not in the form of a ring. On both eggs there are a very 
few quite dark brown well-defined marks. The egg in the Yellow Bunting’s 
nest resembles well the eggs of the foster, but is a little darker. That in the 
nest of the Hedge Sparrow is, of course, conspicuous. There are two foster 
species. 
