VULTURES. 273 



specks in the blue sky each bird is keeping silent watch not only of all that tran- 

 spires below him, but of every movement of his more or less distant companions. 

 Thus it is sufficient if but one bird discover anything eatable; his change of move- 

 ment at once signals his discovery to his nearest companion, who hastens to share the 

 feast. His eagerness betrays his secret to other watchful eyes, and so by an almost 

 faultless, yet unintended, system, the news is noiselessly spread for miles almost before 

 the original discoverer has reached his prize. If the find be small, such, for example, 

 as a dead rat or small snake, the lucky finder disposes of it without assistance and soon 

 resumes his regular and well-understood motions, thus checking the arriving guests 

 almost as soon as they have received their invitations. 



If, on the other hand, the supply of food in prospect is large, the invitation may be 

 spread indefinitely, and if the meat be fresh, and covered by a hide too tough to be at 

 once torn, there is nothing to do but to wait until decomposition shall have softened 

 it, or some carnivorous quadruped shall make an opening, thus giving time for some of 

 the birds to come from great distances, often, perhaps, a hundred miles or more. 



The great bulk of the diurnal birds of prey are included in the family FALCONID^E, 

 to which we now turn our attention. Here we find the largest as well as the smallest 

 of the Accipitres, and the one similar plan on which all are constructed is expressed 

 in so many different ways, and with such endless variations of detail, that at first one 

 is sorely puzzled to know which should be considered the higher and which the lower 

 forms. It would be impossible, however, to arrange the species in any linear series 

 which should show with even tolerable accuracy their true relations, and we shall 

 hence simply assume that the vultures are the lowest, and the falcons the highest, and 

 arrange the intervening groups as best we may, merely remarking that while we here 

 recognize eight sub-families, as being more in conformity with general usage, half as 

 many would, perhaps, answer equally well, and there is much to be said in favor of 

 Mr. Ridgway's proposition to make but two, namely, the Buteoninre and Falconiiue. 

 The purely osteological characters, however, on which these are founded are hardly 

 so suitable for the present purpose as the more superficial ones by which the more 

 numerous divisions which we here adopt are usually defined. 



These sub-families are : The Vulturinae, or Old World vultures ; the Aquilinre, in- 

 cluding the eagles and buzzards ; Pandioninoe, with its single species, the osprey ; 

 Circinje, the harriers ; Milvinoe, the kites ; Polyborince, the carrion-buzzards ; Accipi- 

 .trina?, the true hawks ; and Falconince, the falcons. 



Collectively, the Falconidre may be defined as those diurnal Raptores with imper- 

 forate nostrils, in which the legs are either short or of only moderate length, the tarsus 

 never exceeding six inches. If, for the moment, we leave out of consideration the 

 Vulturina?, whose structure will be noticed shortly, we may add that the head is al- 

 ways largely feathered, the bill strongly hooked, and the claws curved and sharp. 

 The minor modifications, as well as the habits, of the birds comprised in this populous 

 family will be most conveniently noted under the sub-families to which they belong. 



The Vulturinae, or Old World vultures, form a group of carrion-feeding Raptores, 

 which may be recognized by the following characters : Head and neck more or less 

 destitute of feathers, either bare or else bristly or downy, no true feathers on the top 

 of the head. Feet robust and strong, but not very flexible; hind toe inserted at the 

 same level as the rest. Size large, length from bill to tip of tail two to four feet. 

 Young fed at first by regurgitation, later probably by food carried to them in the 

 claws by the old birds. 

 VOL. iv. 18 



