A good classification of the various domestic breeds is extremely difficult, owing to the manner in which many of the forms graduate into each other; but it is curious how exactly the same difficulties are encountered, and the same rules have to be followed, as in the classification of any natural but difficult group of organic beings. An "artificial classification" might be followed which would present fewer difficulties than a "natural classification;" but then it would interrupt many plain affinities. Extreme forms can readily be defined; but intermediate and troublesome forms often destroy our definitions. Forms which may be called "aberrant" must sometimes be included within groups to which they do not accurately belong. Characters of all kinds must be used; but as with birds in a state of nature, those afforded by the beak are the best and most readily appreciated. It is not possible to weigh the importance of all the characters which have to be used so as to make the groups and sub-groups of equal value. Lastly, a group may contain only one race, and another and less distinctly defined group may contain several races and sub-races, and in this case it is difficult, as in the classification of natural species, to avoid placing too high a value on the number of forms which a group may contain.
In my measurements I have never trusted to the eye; and when speaking of a part being large or small, I always refer to the wild rock-pigeon (Columba livia) as the standard of comparison. The measurements are given in decimals of an inch.
(5/5. As I so often refer to the size of the C. livia, or rock-pigeon, it may be convenient to give the mean between the measurements of two wild birds, kindly sent me by Dr. Edmondstone from the Shetland Islands.
LENGTH IN INCHES:
From feathered base of beak to end of tail: 14.25 From feathered base of beak to oil-gland: 9.5 From tip of beak to end of tail: 15.02 Of tail-feathers: 4.62 From tip to tip of wing: 26.75 Of folded wing: 9.25 Beak.--Length from tip of beak to feathered base: .77 Beak.--Thickness, measured vertically at distal end of nostrils: .23 Beak.--Breadth, measured at same place: .16 Feet.--From end of middle toe (without claw) to distal end of tibia: 2.77 Feet.--From end of middle toe to end of hind toe (without claws): 2.02
WEIGHT: 14 1/4 ounces.)
(FIGURE 17. THE ROCK PIGEON, or Columba livia. The parent-form of all domesticated Pigeons. (5/6. This drawing was made from a dead bird. The six following figures were drawn with great care by Mr. Luke Wells from living birds selected by Mr. Tegetmeier. It may be confidently asserted that the characters of the six breeds which have been figured are not in the least exaggerated.))
DIAGRAM 1. DOMESTIC PIGEONS.
Columba livia or ROCK-PIGEON--
--GROUP I.--(SUB-GROUP (RACE) 1.)--German P. --Lille P.-- --Dutch P. --ENGLISH POUTER.
--GROUP II.--(SUB-GROUPS (RACES) 2, 3, 4.)--Kali-Par--Bussora-- --Murassa. --Dragon--ENGLISH CARRIER. --Bagadotten--Scanderoon--Pigeon Cygne--RUNT. --TRONFO. --BARB.
--GROUP III.--(SUB-GROUPS (RACES) 5, 6, 7, 8, 9.)-- --Java Fantail--FANTAIL --Turbit--AFRICAN OWL. --Persian Tumbler--Lotan Tumbler--Common Tumbler--SHORT-FACED TUMBLER. --INDIAN FRILL-BACK. --JACOBIN.
--GROUP IV.--(SUB-GROUPS (RACES) 10, 11.)-- --TRUMPETER. --LAUGHER. --ENGLISH FRILL-BACK. --NUN. --SPOT. --SWALLOW. --DOVECOTE PIGEON.
I will now give a brief description of all the principal breeds. Diagram 1. may aid the reader in learning their names and seeing their affinities. The rock-pigeon, or Columba livia (including under this name two or three closely-allied sub-species or geographical races, hereafter to be described), may be confidently viewed, as we shall see in the next chapter, as the common parent-form. The names in italics on the right-hand side of the page show us the most distinct breeds, or those which have undergone the greatest amount of modification.