=Description.= The adult peacock is so much more striking in appearance than the females and the young males, and old males are so often exhibited alone, that many persons suppose that the peafowl are distinctly unlike other domestic birds. The size, shape, and carriage of the peacock sometimes suggest to them a resemblance to the turkey gobbler, but the peacock's most striking characters seem so peculiar to it that the attention of the observer is usually fixed upon them, to the exclusion of direct comparisons with other creatures. When, however, one sees a flock containing several females, or males in which the characteristic plumage is not yet developed, the general resemblance between peafowl and turkeys is immediately noticed. The peafowl is smaller, slenderer, and more graceful than the turkey, and is a little more agile in motion. But if there were no old males present to identify the species, to which they belong, a person who was not familiar with peafowls, seeing a flock for the first time, would be almost certain to think that they were turkeys of a rare breed. Notwithstanding this striking general likeness, a close observer will soon note that in nearly every conspicuous character the differences between the two indicate that they belong to entirely different species. The voice of the peafowl is a harsh, piercing scream. [Illustration: Fig. 167. Indian Peacock. (Photograph from the New York Zoölogical Society)] The development of the plumage in the male at full maturity is like that of the fowl and of some pheasants. In all of these species in which the tail of the male assumes a highly decorative form, it is not the tail proper that is so developed, but the tail coverts and other feathers of the back, which in the male are long and flowing. In the peacock these feathers are very remarkably developed, both in form and in color. The largest are sometimes a yard long. The stem, or shaft, is a marvelous combination of lightness and strength. For the greater part of the length of the shaft the barbs are so far apart that they do not form a web, but make a fringe on each side. Toward the tip of the feather the barbs are closer together, and at the extremity they form a broad web. The feathers of this structure growing next to the main tail feathers are the longest. The next are a little shorter, and thus the length diminishes until the shortest coverts are only a little longer than the ordinary feathers of the back. This feather formation is called the train. The train of the peacock is the most prominent peculiarity of the species, but there is also in both sexes another uncommon feather character--the curious little tuft, or crest (called the aigret), which grows on the head.