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Titlark's, or Wagtail's nest would do as did her mother. Furthermore it is unquestionable that 

 whatever variation there may be among the eggs laid by different individuals of the same species, 

 there is a strong family likeness between the eggs laid by the same individual, even at the 

 interval of many years ; and it can hardly be questioned that the eggs of the daughter would 

 more or less resemble those of her mother. Hence the supposition may be fairly entertained that 

 the habit of laying a particular style of egg is also likely to become hereditary. Combining this 

 supposition with that as to the Cuckow's habit of using the nest of the same species becoming 

 hereditary, it will be seen that it requires but an application of the principle of ' Natural 

 Selection ' to show the probability of this principle operating in the course of time to produce 

 the facts asserted by the anonymous Solognot of the last century and by Dr. Baldamus and 

 others since. The particular gens of Cuckow which inherited and transmitted the habit of 

 depositing in the nests of any particular species of bird eggs having more or less resemblance to 

 the eggs of that species, would prosper most in those members of the gens where the likeness 

 was strongest ; and the other members would (cceteris paribus) in time be eliminated. As already 

 shown, it is not to be supposed that all species, or even all individuals of a species, are duped 

 with equal ease. The operation of this kind of natural selection would be most needed in those 

 cases which occur the least frequently. Here it is we find it ; for observation shows that eggs of 

 the Cuckow deposited in nests of the Red-backed Shrike (Lanius collurio), of the Bunting 

 (Emberiza miliaria), and of the Icterine Warbler, approximate in their colouring to eggs of those 

 species — species in whose nests the Cuckow rarely (in comparison with others) deposits eggs. 

 Of species which are more easily duped, such as the Hedge-Sparrow, mention has already been 

 made." There is much in what Professor Newton has written that deserves the most earnest 

 attention ; and it is highly probable that, as he suggests, an hereditary tendency may be trans- 

 mitted by a female Cuckoo to her posterity ; but he appears to reckon only on this tendency 

 being transmitted by the female. Would not the male also have some influence in this direction ? 

 And then the question arises as to how it would show itself; for the female Cuckoo is most 

 irregular in her matrimonial arrangements, and has connexion not only with one male but with 

 as many different lovers as she can conveniently visit during her peregrinations. Possibly this 

 irregularity in the matrimonial arrangements of the Cuckoo may to some extent account for the 

 very uncertain way in which the hereditary tendency (supposing such to exist) exhibits itself. 

 Altogether the entire question is so enveloped in mystery that it naturally gives rise to numerous 

 surmises, scarcely any of which can be satisfactorily gauged by a series of positively ascertained 

 facts. 



Mr. G. Dawson Rowley, and several other ornithologists, have given lists of the different 

 species of birds to which the Cuckoo has been known to intrust her eggs ; but I have found 

 many other species recorded which do not seem to be included in any of these lists, and it may 

 therefore be interesting to my readers to have as complete a list as I am able to make out. In 

 so doing I take the opportunity of expressing my thanks to Mr. E. Bidwell, who had already 

 made a manuscript list, purposing to publish it, which he has kindly lent to me. Those species 

 in whose nests the eggs of the Cuckoo have been found in Great Britain are designated by an 

 asterisk (*) ; and in every instance where the occurrence has not been recorded by at least three 

 or four authors, the authority is given in brackets after the name. 



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