42 BULLETIN 16 7, UNITED STATES NATIONAL MUSEUM 



hiss and low guff, guff, guff, like a dog barking in the distance." 

 Pennock describes a ciy as sounding like watt or waugh. The 

 blowing sound resembles that made by bellows. Donald J. Nichol- 

 son (1928b) says that the young hiss at an intruder and utter a 

 blowing note very similar to that of a rattlesnake. Edward S. 

 Thomas (1928) writes: 



The birds were heard to give a variety of notes. Adults and young, when 

 cornered or annoyed, give a rasping, hissing snarl, also described as a "snore", 

 and "half-way between a wheeze and a squeel." The young give this fre- 

 quently in the presence of the parents. The young also frequently make a 

 sound which, when they were very young, was described as "Phuh!" or 

 "Whuh!" Later this note became in the older birds, "Woof!" or "Wooft !" 

 This note apparently denotes suspicion, and may be the counterpart of a grunt- 

 ing sound which the adults frequently emit. In addition, I heard the adult 

 give a low, croaking "Coo," very much like a one-syllabled coo of the domestic 

 pigeon. 



Field marks. — When this bird is seen at close range, alighted on 

 the ground or on a tree, it is unmistakable. Its black head and neck 

 bare of feathers proclaim it to be a black vulture, although it must 

 be remembered that the head of the immature turkey vulture is also 

 dark and not red as in the adult. The other characteristics of the 

 black vulture are best seen in flight. Here its short, nearly square- 

 ended tail, as contrasted with the longer rounded tail of the turkey 

 vulture, is evident. The feet may sometimes be seen against the tail 

 as they reach nearly to the end and even project a little, but it is 

 more difficult to see them in the turkey vulture. The wings seen 

 from above and below both show a light-colored space at the outer 

 end of the primaries, while in the turkey vulture all the primaries 

 and secondaries are light colored, giving the effect of a light posterior 

 border to the wings. While the wings of the turkey vulture are 

 held up at an angle in soaring, those of the black species are as a 

 rule more nearly horizontal, and the ends of the primaries are more 

 distinct and spread out like fingers. The heavier, clumsier flight of 

 the black vulture, with frequent flappings of the wings, easily dis- 

 tinguishes the two birds, although in very favorable airs the black 

 vulture may soar nearly as well as the turkey vulture. 



Enemies. — The black vulture is fortunate in having few if any 

 enemies. Eagles and wolves may chase it away from a carcass, and 

 ospreys may wrathfully pursue it if it appropriates a fish from the 

 osprey's nest. Even man treats it with consideration in return for 

 its services in cleaning up carrion and offal, although in time most 

 southern cities may adopt the more sanitary but more expensive 

 methods needed in northern cities in order to escape the defilements 

 of these scavenger birds. In some regions, as has already been men- 

 tioned under "Food", it may be necessary for man to control these 

 birds when they kill j^oung domestic animals. 



