34 THE OENITHOLOGIST. 



OBSERVATIONS AMD QUERIES. 



The Eggs of the Common Cuckoo. — Mr. Marsden's article on the 

 eggs of the Cuckoo has doubtless been read with much interest, as his 

 experience with them must be a very large one. Perhaps in some future 

 number he may tell us if he has met with many instances of assimilation of 

 the Cuckoo's egg to those of the foster-parent, and if he has had a blue 

 specimen of the egg from any part of this country. Our own series of 

 Cuckoo's eggs only contains about forty examples, of which fourteen were 

 found by myself, and of the rest, all but three came into my hands unblown ; 

 about one-third have more or less gloss on the shell. The hardness of the 

 shell seems to be an invariable feature, and not unfrequently the yolk is 

 -somewhat peculiar in colouring, with either a greenish or brownish tinge. 

 One day in June, 1894, I found a Pied Wagtail's nest, containing four eggs 

 of the owner and one Cuckoo's egg, in a garden in this village, and later in 

 the day a second Pied Wagtail's nest, also containing four eggs of the owner 

 and one of the Cuckoo, in my own garden, less than half-a-mile from the 

 first nest. The two Cuckoo's eggs were so exactly alike that I felt almost 

 certain they were laid by the same hen, and when I blew them I found each 

 egg had a brownish-yellow yolk, in colour much resembling a dark-coloured 

 pheasant's egg. Three times in the last few years clutches of five eggs of 

 the Skylark have been brought me, in each case containing an " odd egg," 

 but only one of these odd eggs was at all doubtful, and though at first we 

 hoped it might be a Cuckoo's egg, it showed, when blown, the thin shell and 

 richly-coloured yolk of the Skylark's egg. I think there is reason to fear that 

 sometimes a genuine Cuckoo's egg is placed with a clutch to which it was 

 never added by the Cuckoo herself, for, if the eggs are blown, one must be 

 entirely dependent on the integrity of the person from whom they are 

 received. Perhaps the most interesting egg we have is one with a clutch of 

 three Bullfinch's, which were brought me by a boy in May, 1893. At first I 

 was rather inclined to be incredulous, but when it came to blowing the eggs 

 all proved to be in the same stage of incubation, and I have always believed 

 the clutch to be perfectly genuine. One of the finest eggs we have I found 

 in a nest containing two lively young Hedge-sparrows, about three or four 

 days old, and in this egg the embryo was dead and partly decomposed. It is 

 difficult to understand why the Cuckoo's egg should be so frequently 

 found in the nest of the Red-backed Shrike on the Continent, and so rarely 

 in England ; only one instance has occurred here, and then the Shrike's nest 

 contained no other egg than the Cuckoo's, and was possibly deserted when 

 visited by the hen Cuckoo. I should like to try experiments in weighing 

 eggs like those described by Mr. Marsden, but the lack of necessary apparatus 



