COLUMBID^, PIGEONS. 223 



Order OOLUMBll. Columbine Birds. 



An cssenti.il charfieter of l>irds of this order is seen in tlie strncturo of tlie bill : 

 horny and convex at tlie tip, somewhat contracted in the continnit)', furnished at the 

 base with a soft swollen memln-ane in which the nostrils open. There are fonr toes, 

 three anterior, generally cleft, but occasionally with a slight basal web, and one 

 behind, with few exceptions perfectljr insistent or not obviously elevated. The feet 

 are never lengthened ; the tarsus is commonly shorter than the toes, either scutellate 

 or extensively feathered anteriorlj', reticulate on the sides and behind, the envelope 

 rather membranous than corneous. The plumage is destitute of aftershafts. Tlie 

 sj'rinx has one pair of intrinsic muscles. There are two carotids. The sternum is 

 doubly notched, or notched and fenestrate ; tiiere are other osteological characters. 

 The regimen is exclusively vegetarian. Terrestrial progression gradient, never 

 saltatory. As commonly accepted, the order is composed of three families. The 

 strange dodo, Didus ineptus, recently extinct, represents one, Didklre; another, 

 Didunculidce, consists of the only less singular tooth-billed pigeon, Didunculiis strigi- 

 rostris, of the Navigator Islands ; the third is the ColumbidcE. Some, like Lillje- 

 borg, enlarge the order, under name of Pullastrfp, to receive the Craeidre (see 

 beyond), and llegcvpodkhe, big-feet or mound-birds of tlie East Indies ; mainly on 

 account, it would appear, of the position of the hallux in these families ; but the 

 balance of evidence favors their reference to the gallinaceous birds. There is no 

 question that the columbine are A'er}' closelj' related to the rasorial birds, but it 

 seems best to draw the line between them as above indicated ; and I shall accord- 

 ingly' close the great Insessorial series with the 



Family COLUMBID^. Pigeons. 



The family may he framed simply hy exclusion of the Bidanculida; and Dldklw. 

 With one exception, all our species will be immediatelj^ recognized by their likeness 

 to the familiar inmates of the dove-cot. One seemingly trivial circumstance is so 

 constant as to become a good clue to these birds : the frontal feathers do not form 

 antiiB by extension on either side of the cnlmen, but sweep across tlie base of the 

 bill with a strongly convex outline projected on the cnlmen, thence rapidlj' retreat- 

 ing to the commissural point. The plumnleless plumage is generally compact, with 

 thickened, spongy rhachis, the insertion of which will seem loose to one who skins 

 a bird of this family. The head is remarkably small ; the neck moderate ; the 

 body full, especially in the pectoral region. The wings are strong, generally 

 lengthened and pointed, conferring a rapid, powerful, whistling flight ; the peculiar 

 aerial evolutions that these birds are wont to perform, have furnished a synonym for 

 the family, Oyranies. The tail varies in shape, from square to graduate, but is 

 never forked; as a rule there are 12 rectrices, frequentljr increased to 14, rarely 

 to 16. The feet show considerable modification when the strictly arboricole are 

 compared with the more terrestrial species ; their general character has just been 

 indicated. The gizzard is large and muscular, particnlarlj^ in tli€ species that feed 

 on seeds and other hard fruits ; the gullet dilates to form a capacious circumscribed 

 crop. This organ at times secretes a peculiar milky fluid, which, mixed with 

 macerated food, is poured by regurgitation directlj^ into the mouth of the youno- ; 

 thus the fabled "pigeon's milk" has a strong spice of fact, and in this remarkable 

 circumstance we see probably the nearest approach, among birds, to the character- 



