Common Cuckoo. 285 



nacea) : and that on that account eggs of such colouring form the 

 most frequent exceptions; that is to say, are most frequently 

 found in the nests of other species. Thus too, lastty, it comes to 

 pass that these two above-named prevailing colours of the 

 Cuckoo's eggs are spread over most localities, whilst at the same 

 time they also appear, almost everywhere, as exceptions in other 

 nests. For the diffusion of 'these two species (the common 

 White-throat and the Pied Wagtail) is very extensive, and their 

 haunts usually offer to the Cuckoo also the requirements of its 

 existence: it is therefore not without signification that one 

 seldom finds in their nests Cuckoos' eggs of other colours, but one 

 does very frequently find in the nests of other birds Cuckoos' eggs 

 of their type.' 



[I will just quote, before I take leave of Dr. Baldamus, the 

 three following deductions, which he draws from his observations, 

 and with which he concludes his treatise. 



I. * Nature must have some special motive in the circum- 

 stances above detailed, so many, so connected together, but so 

 peculiar. 



II. ' That motive is plainly to be seen : viz., that by means of 

 certain laws originally made she may ensure and facilitate the 

 preservation of a species otherwise much exposed to danger. 



III. ' She attains this end by a very simple method : in that she 

 invests every hen Cuckoo with the faculty of laying eggs 

 coloured like the eggs of the bird of whose nest she prefers to 

 make use, according to the locality; or, in other words, every 

 hen Cuckoo lays eggs only of a fixed colour, corresponding with 

 the eggs of that Warbler in whose nest she lays them (as a 

 general rule) : and she only lays in other nests when, at the time 

 for her laying, one of the species of her own peculiar type, as we 

 may say, which is fitted for her in every particular, is not 

 ready.'] 



Such is the very interesting and well sustained argument of Dr. 

 Baldamus ; and however new and startling his hypothesis, how- 

 ever unprecedented his conclusions, yet he supports his argument 

 with such a battery of facts that his position seems almost im- 



