The third order of Carinate Birds is that of the Rasores, or Scratchers, often spoken of collectively as the "Gallinaceous" birds, from the old name of "Gallinae," given to the order by Linnaeus. The Rasores are characterised by the convex, vaulted upper mandible, having the nostrils pierced in a membranous space at its base. The nostrils are covered by a cartilaginous scale. Taking the Gallinacei as the type of the order, the legs are strong and robust, mostly covered with feathers as far as the joint between the tibia and tarso-metatarsus. There are four toes, three in front and one behind, the latter being short, and placed at a higher level than the other toes. All the toes terminate in strong blunt claws suitable for scratching (fig. 338, A). The food of the Scratchers or Gallinaceous birds consists chiefly of hard grains and seeds, and in accordance with this they have a capacious crop and an extremely strong and muscular gizzard. They mostly nidificate, or build their nests, upon the ground, and the more typical members of the order are polygamous. The males take no part in either nidification or incubation, and the young are generally "precocious," being able to run about and provide themselves with food from the moment they quit the egg. The young of the Pigeons and Doves, however, are brought forth in a comparatively helpless condition. The wings in the majority of the Rasores are more or less weak, and the flight is feeble and accompanied with a whirring sound. Many of the Pigeons, however, are capable of very powerful and sustained flight.
Fig. 338. - Rasores. A, Foot of Fowl (Gallus Bankiva); B, Head of Guinea-fowl.
The order Rasores is divided into two sub-orders, called respectively the Gallinacei and the Columbacei, or sometimes, from the characters of the sounds which they utter, the Clama-tores and the Gemitores.
This sub-order comprises the typical members of the order Rasores, such as the common Fowls, Turkeys, Partridge, Grouse, Pea-fowl, and a number of allied forms. Its characters are therefore those of the order itself, but it is especially distinguished from the Columbacei by being less fully adapted for flight. The body is much heavier, comparatively speaking, the legs and feet are stronger, and the wings shorter and less powerful. On the whole, therefore, these birds are worse fliers than the Columbacei, and are better adapted for living upon the ground. The hallux (fig. 339, A) is elevated above the anterior toes, and merely touches the ground in walking. The back of the tarsus, too, is usually furnished in the males with a spur (calcar), which is used as an offensive weapon, and has sometimes been looked upon as a rudimentary toe.* Lastly, the Gallinacei are mostly polygamous, and the males are usually much more brilliantly coloured than the females, this being an adaptive modification of the plumage to meet this peculiarity in their mode of life. †
The following are the most important families of the Gallinacei:
The Telraonidae, or Grouse family, comprises the various species of Grouse (Tetrad), the Ruffed Grouse (Bo-nasa), the Cock of the Plains (Centrocercus), and the Ptarmigans (Lagopns).
The Perdicidae, or Partridge family, comprises the Partridges (Perdix), the Francolins (Francolinus), the Quails (Coturnix), the Maryland Quail (Ortyx), the Tufted Quails (Lophor-tyx), etc.
The Phasianidae, or Pheasant family, comprises the Turkeys and Guinea-fowl (Meleagrinae), the common Pheasant (Phasianus Colchicus), the Golden and Silver Pheasants, the common Fowl (Gallus domesticus), and the Pea-fowl (Pavoninae). None of these birds - all of which can be domesticated, and most of which are of great value to man - are natives of this country, though they will all breed readily, and thrive even in confinement. The domestic Turkey (Meleagris gallopavo) is originally a native of North America, where it still occurs in a wild condition, having been brought to Europe about the beginning of the sixteenth century. The Guinea-fowl (Numida meleagris) is originally an African bird. The common Pheasant (Phasianus Colchicus), though now regarded as an indigenous bird, truly belongs to Asia, and it is asserted that it was really brought to Europe from Colchis by the Greeks; hence its specific name. The common Fowl is certainly not a native of Europe, and it is usually thought to be a native of Asia or of some of the Asiatic islands; but its exact original habitat is uncertain, as is the species from which the domestic breeds are descended (commonly said to be the Gallus Bankiva of Java). The introduction of the Fowl into Europe is lost in the mists of antiquity, and it is wholly unknown whence the original stock may have been brought; though there is really every ground for believing that the typical breed - the Game breed - is truly descended from the Jungle Cock, or Gallus Bankiva. The domestic Fowl has, however, been found to be a member of the Cave-fauna of France in the early Stone period, which would throw far back its alleged introduction from the East. The Pea-fowl (Pavo) are really natives of Thibet and Hindostan, and were originally brought to Greece by Alexander the Great. They were formerly much esteemed as food, but are now regarded merely from an ornamental point of view.
Fig. 339. - A, Foot of Black-cock (Tetrao tetrix). B and C, Upper and under views of the foot of the Wood-pigeon (Columba palumbus).
* In some cases (as in the Java Peacock) the female possesses spurs as well as the male; and sometimes (as in Polyplectron) there are two or more spurs on each leg of the male.
† The Guinea-fowl, Red Grouse, Ptarmigan, and Partridge are monogamous, in a state of nature at any rate.
The Pteroclidae, or Sand-grouse, are confined to the Old World, being principally Asiatic and African, and in their long and pointed wings they make an approximation to the Pigeons.
The Turniridae, or Bush-quails, on the other hand, make an approach to the Charadriidae. amongst the Grallatores. They are found in Europe, Africa, Asia, and Australia.
The Megapodidae, or Mound-birds, belong to India and Australia, and have very large feet and long claws. They build immense mounds, often six or eight feet high, and twenty or thirty feet in diameter. They lay their eggs in the centre of these mounds at a depth of two or three feet, and leave them to be hatched by the heat produced by the fermentation of the vegetable matter of the mass.
The Cracidae, or Curassows, are large heavy birds, allied to the preceding, belonging to Central and South America, and to a great extent arboreal in their habits. The best-known species is the crested Curassow (Crax alector) of Mexico and Brazil.
Lastly, the Tinamidae, or Tinamous, form an aberrant group of the Gallinacei, with many remarkable features in their internal organisation, and with the striking external character that the tail is exceedingly short or totally wanting. They inhabit South America, and are in many respects intermediate between the Struthionidae and the true Gallinae, such as the Grouse. Many of the sutures of the skull are persistent, and the brain is very small. There is the lacertilian character that there exists a row of supra-orbital bones.