72 "Behold the Birds of the Air" 



to set aside all other considerations, such a supposition 

 would require us to believe that the circumstances which 

 have operated to produce development have been as 

 absolutely identical in all cases as are their results. 

 Every bird precisely similar to another should be de- 

 scended from a line of ancestors which had lived through 

 just the same series of experiences as that other's. Yet 

 it is almost impossible that in the case of any two broods 

 can this be true ; it is abundantly evident that, speaking 

 of the race in general, it is the reverse of the truth. In 

 no two of our own English parishes are the conditions 

 of weather or of food-supply precisely identical ; and if 

 these had been the efficient causes, they should have 

 availed to manifest their influence by varying at least 

 the breadth of an edging or the shape of a spot. What 

 differences of type might we then expect to find in Nor- 

 way and in Palestine ? 



The example chosen is that of a bird so common that 

 its observation is within the reach of all, but it is by no 

 means either solitary or singular. The description of 

 many others furnishes us with minutiae of variations 

 still more remarkable. Let the reader, the first time he 

 has the opportunity, take a good look with a field glass 

 at a Red -start, and observe the colouring of his head. 

 He will find a narrow black band above the bill, a white 

 patch on the forehead, the chin and cheeks jet black, 

 the top of the head lead-grey. Again, to choose a 

 subject which there will probably be more opportunity 

 of handling, he may test upon the first Woodcock he 

 falls in with, the following description of the bird by 

 Yarrell : 



"The beak is dark brown at the point, pale reddish 

 brown at the base. From the beak to the eye a dark 

 brown streak. The colour of the plumage is a mixture, 

 principally of three shades of brown, pale wood-brown, 

 chestnut-brown, and dark umber-brown; each feather 

 on the upper surface of the body contains the three 

 shades, but so disposed as to produce a beautifully 

 variegated appearance. The cheeks pale wood-brown, 



