162 On the Ornithology of Wilts {^Columbidce], 



plane as the other toes (as is the case with the preceding Orders), 

 but upon the tarsus, at a height greater or less according to the 

 running power of the species." ^ It is true that this peculiar for- 

 mation of the foot impedes the members of this Order from grasping 

 a perch with the same firmness and security as the regular perchers, 

 and for this reason most of them roost upon the ground. 



Such are the more prominent characteristics of the Ground birds ; 

 I pass on now to describe the four families and their respective 

 species of which this Order is composed. 



COLUMBID^ (The Doves). 

 It will at once be seen that the Doves occupy an intermediate 

 place between the Perchers and the Ground birds ; and are the 

 connecting link, partaking of the peculiarities of both: thus, though 

 they feed on the ground, they perch readily on trees ; and though 

 they walk with ease and even celerity, yet they have a strong 

 rapid and protracted flight. Thus we pass gradually and almost 

 insensibly from the true Perchers to the typical Ground birds, for 

 nature abhors an abrupt wrench as much as a vacuum, and all is 

 orderly, gentle and harmonious in her arrangement, and we slide 

 on from order to order, and from family to family, and genus and 

 species in successive steps, with no break to disconnect the regular 

 links in our continuous chain. This is sufficiently perceptible in 

 the Doves, even in the limited number of species which belong to 

 this country, and almost all of which (or four out of five), are 

 known in Wiltshire. But if we were to extend our observations 

 through the multitudinous species and even genera which inhabit 

 other countries, we should see this rule very much more applicable, 

 for the Pigeons form a vast staircase of species leading from the 

 trees to the ground ; some being thoroughly arboreal, living and 

 nesting on the trees, and enjoying a rapidity of flight almost unsur- 

 passed : whilst others at the opposite end of the list are as com- 

 pletely terrestrial ; with wings as short and bodies as heav)^ and as 

 incapable of protracted flight as our domestic poultry, and indeed 



* Selby's Illustrations of British Ornitliology, vol. i., p, 103. 



