1114 The Zoologist— March, 1869 



(as I before remarked) are all carefully authenticated, in regard to the 

 nests from which they were taken : all these specimens he examines 

 singly, and describes their colouring as nearly all partaking, in a 

 greater or less degree, of the character, ground colour, and markings 

 of the eggs of the species in whose nests they were severally laid ; 

 while some are so extremely similar that but for the groin* or texture 

 of the shell and certain characteristic specks, it would be difficult to 

 distinguish them apart. The exceptions to this general rule are 

 those laid in the nests of corn-eating species, and our author adds that 

 it would be extraordinary indeed if the cuckoo's eggs should resemble 

 the eggs of these exceptional and never-intended foster-parents. 



" The fact then," says Dr. Baldamus, " is quite established and 

 beyond all doubt, that there are cuckoo's eggs which, both in colour 

 and in marking, are very like the eggs of those species in whose nests 

 they are generally laid ;" and then he proceeds to argue that Nature, 

 who never trifles nor acts without purpose, has plainly given the parent 

 cuckoo this faculty, in order to facilitate the continuance of the species 

 under peculiar conditions ; for (he well remarks) had this not been so, 

 we are driven to the alternative that the warblers and others, which 

 generally recognize so easily all strange eggs, casting them out of the 

 nest,t or else deserting it, in regard to the cuckoo's eggs are quite 

 blind, and cannot recognize the red eggs among their green clutches,! 

 and vice versa. " Therefore," continues our author, " 1 do not hesitate 

 to set forth, as a law of Nature, that the eggs of the cuckoo are in a 

 very considerable degree coloured and marked, like the eggs of those 

 birds in whose nests they are about to be laid, in order that they 

 might the less easily be recognized by the foster-parents, as sub- 

 stituted." § 



* " Das Kovn :" the German word exactly answering to our English idiom 

 "grain." The grain or texture of the shell is too often overlooked by oologists, but 

 amongst the very similar eggs of some species, as more particularly among the duck 

 tribe, this is one very important means of identification, more especially when the egg 

 is placed under a low magnifying power. 



t Montagu's ' Ornithological Dictionary,' Introduction, p. iv. 



J Or " loiters " as our Wiltshire rustics say : " gelege " in German. 



§ It is worthy of remark that, whereas it has been often asserted that the egg of 

 the cuckoo is by no means found in any proportion to the number of old birds (for it is 

 not a rare species), and every female would seem to lay annually from four to six eggs, 

 the difficulty is at once disposed of, if Dr. Baldamus' theory is correct, inasmuch as the 

 great similarity of pje egg of the cuckoo to those of the nest iu which it is placed, may 

 deceive human eyes no less than those of the foster-parents. 



