"The structure and habits of the family or group of pigeons are so peculiar and so strikingly distinct from those of any other birds, that they demand special attention. The pigeons were formerly classed by the majority of naturalists along with the , the true poultry, and by others with the or -like birds; but more accurate observation has rendered evident the fact that they form a perfectly distinct family, distinguished from all other birds by the singular manner in which their young are nourished. Unlike the true gallinaceae—which are hatched in a very perfect state and able to follow the parent hen within a few hours after birth—the young pigeons are born in a most immature and helpless condition, and are fed with a curdy secretion, produced in the crops of the parents, the "soft food" of the pigeon-fancier. This is expressly produces at the period of hatching, for the support of the callow young."