416 BRITISH BIRDS. 
Family PHASIANIDA, orn GAME BIRDS. 
The Game Birds form a large and somewhat ill-defined group. Sclater 
places them between the Pigeons and the Rails. Forbes associated the 
Sand-Grouse and the Hemipodes with the Pigeons, the Plovers, the Gulls, 
and allied birds ; whilst he placed the true Game Birds with the Cuckoos, 
the Bustards, and the Rails. In the Game Birds the two notches on each 
side of the sternum are so deep that the exterior portion appears to have 
lost its character, the broad sternum appearing very narrow and flanked 
by two lateral processes resembling abnormally developed ribs; but the 
sternum of the Sand-Grouse is exceptional in this respect, and somewhat 
resembles that of the Pigeons. The modification of the cranial bones 
resembles that of the Pigeons, Sandpipers, Gulls, Auks, &e. The ptery- 
losis of the Game Birds is very specialized; but that of the Guinea-fowls 
and Grouse leads on through the Sanud-Grouse to the Pigeons. Their 
myology, on the other hand, is very generalized, but shows affinities with 
the more highly developed muscular systems of the Sandpipers and other 
families of Waders. According to Gadow, their digestive organs are 
nearest allied to those of the Rails. 
There is no family of birds in which there is more variation in the 
changes of plumage than in the Game Birds. The young are able to fly 
very soon after they are hatched ; and during the period of growth some 
of the quills are always being replaced by new feathers slightly larger than 
the old ones, so that, before the young bird has arrived at its full size, all 
the quill-feathers have been changed one after another three or four times 
~ over, the last change taking place about the time when the autumnal moult 
of the parent birds occurs. In all Game Birds this autumnal moult is the 
only complete one that takes place, and it is not known that the Pheasant 
has any other. In the Partridges and Quails a partial spring moult, 
apparently confined to the feathers of the head and neck, takes place. 
According to Meves, the Black Grouse has a similar partial spring moult. 
It is not known that the Red Grouse has a spring moult ; but its very near 
ally, the Willow-Grouse, changes the colour of most of its small feathers in 
spring and moults them in autumn. Macgillivray says that the Ptarmigan 
has four nearly complete new sets of small feathers every year, the winter 
plumage being retained for nearly six months, the spring plumage being 
assumed in May. Incubation takes place in June; and from July to 
November a slow but continuous moult of the small feathers occurs, 
